jack2/linux/alsa/JackAlsaDriver.cpp

/*
Copyright (C) 2001 Paul Davis
Copyright (C) 2004 Grame

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include <iostream>
#include <math.h>
#include <stdio.h>
#include <memory.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <stdarg.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/time.h>
#include <regex.h>
#include <string.h>

#include "JackAlsaDriver.h"
#include "JackEngineControl.h"
#include "JackClientControl.h"
#include "JackPort.h"
#include "JackGraphManager.h"
#include "JackLockedEngine.h"
#include "JackPosixThread.h"
#include "JackCompilerDeps.h"
#include "hammerfall.h"
#include "hdsp.h"
#include "ice1712.h"
#include "usx2y.h"
#include "generic.h"
#include "memops.h"

namespace Jack
{

#define jack_get_microseconds GetMicroSeconds

/* Delay (in process calls) before jackd will report an xrun */
#define XRUN_REPORT_DELAY 0

void
JackAlsaDriver::alsa_driver_release_channel_dependent_memory (alsa_driver_t *driver)
{
    bitset_destroy (&driver->channels_done);
    bitset_destroy (&driver->channels_not_done);

    if (driver->playback_addr) {
        free (driver->playback_addr);
        driver->playback_addr = 0;
    }

    if (driver->capture_addr) {
        free (driver->capture_addr);
        driver->capture_addr = 0;
    }

    if (driver->playback_interleave_skip) {
        free (driver->playback_interleave_skip);
        driver->playback_interleave_skip = NULL;
    }

    if (driver->capture_interleave_skip) {
        free (driver->capture_interleave_skip);
        driver->capture_interleave_skip = NULL;
    }

    if (driver->silent) {
        free (driver->silent);
        driver->silent = 0;
    }

    if (driver->dither_state) {
        free (driver->dither_state);
        driver->dither_state = 0;
    }
}

int
JackAlsaDriver::alsa_driver_check_capabilities (alsa_driver_t *driver)
{
    return 0;
}

int
JackAlsaDriver::alsa_driver_check_card_type (alsa_driver_t *driver)
{
    int err;
    snd_ctl_card_info_t *card_info;
    char * ctl_name;
    regex_t expression;

    snd_ctl_card_info_alloca (&card_info);

    regcomp(&expression, "(plug)?hw:[0-9](,[0-9])?", REG_ICASE | REG_EXTENDED);

    if (!regexec(&expression, driver->alsa_name_playback, 0, NULL, 0)) {
        /* the user wants a hw or plughw device, the ctl name
         * should be hw:x where x is the card number */

        char tmp[5];
        strncpy(tmp, strstr(driver->alsa_name_playback, "hw"), 4);
        tmp[4] = '\0';
        jack_log("control device %s", tmp);
        ctl_name = strdup(tmp);
    } else {
        ctl_name = strdup(driver->alsa_name_playback);
    }

    // XXX: I don't know the "right" way to do this. Which to use
    // driver->alsa_name_playback or driver->alsa_name_capture.
    if ((err = snd_ctl_open (&driver->ctl_handle, ctl_name, 0)) < 0) {
        jack_error ("control open \"%s\" (%s)", ctl_name,
                    snd_strerror(err));
        return -1;
    }

    if ((err = snd_ctl_card_info(driver->ctl_handle, card_info)) < 0) {
        jack_error ("control hardware info \"%s\" (%s)",
                    driver->alsa_name_playback, snd_strerror (err));
        snd_ctl_close (driver->ctl_handle);
        return -1;
    }

    driver->alsa_driver = strdup(snd_ctl_card_info_get_driver (card_info));
    jack_info("Using ALSA driver %s running on %s", driver->alsa_driver, snd_ctl_card_info_get_longname(card_info));

    regfree(&expression);
    free(ctl_name);

    return alsa_driver_check_capabilities (driver);
}

int
JackAlsaDriver::alsa_driver_hammerfall_hardware (alsa_driver_t *driver)
{
    driver->hw = jack_alsa_hammerfall_hw_new (driver);
    return 0;
}

int
JackAlsaDriver::alsa_driver_hdsp_hardware (alsa_driver_t *driver)
{
    driver->hw = jack_alsa_hdsp_hw_new (driver);
    return 0;
}

int
JackAlsaDriver::alsa_driver_ice1712_hardware (alsa_driver_t *driver)
{
    driver->hw = jack_alsa_ice1712_hw_new (driver);
    return 0;
}

int
JackAlsaDriver::alsa_driver_usx2y_hardware (alsa_driver_t *driver)
{
    // TODO : will need so deeped redesign
    // driver->hw = jack_alsa_usx2y_hw_new (driver);
    return 0;
}

int
JackAlsaDriver::alsa_driver_generic_hardware (alsa_driver_t *driver)
{
    driver->hw = jack_alsa_generic_hw_new (driver);
    return 0;
}

int
JackAlsaDriver::alsa_driver_hw_specific (alsa_driver_t *driver, int hw_monitoring,
        int hw_metering)
{
    int err;

    if (!strcmp(driver->alsa_driver, "RME9652")) {
        if ((err = alsa_driver_hammerfall_hardware (driver)) != 0) {
            return err;
        }
    } else if (!strcmp(driver->alsa_driver, "H-DSP")) {
        if ((err = alsa_driver_hdsp_hardware (driver)) != 0) {
            return err;
        }
    } else if (!strcmp(driver->alsa_driver, "ICE1712")) {
        if ((err = alsa_driver_ice1712_hardware (driver)) != 0) {
            return err;
        }
    } /*else if (!strcmp(driver->alsa_driver, "USB US-X2Y")) {
        if ((err = alsa_driver_usx2y_hardware (driver)) != 0) {
            return err;
        }
    } */else {
        if ((err = alsa_driver_generic_hardware (driver)) != 0) {
            return err;
        }
    }

    if (driver->hw->capabilities & Cap_HardwareMonitoring) {
        driver->has_hw_monitoring = TRUE;
        /* XXX need to ensure that this is really FALSE or
         * TRUE or whatever*/
        driver->hw_monitoring = hw_monitoring;
    } else {
        driver->has_hw_monitoring = FALSE;
        driver->hw_monitoring = FALSE;
    }

    if (driver->hw->capabilities & Cap_ClockLockReporting) {
        driver->has_clock_sync_reporting = TRUE;
    } else {
        driver->has_clock_sync_reporting = FALSE;
    }

    if (driver->hw->capabilities & Cap_HardwareMetering) {
        driver->has_hw_metering = TRUE;
        driver->hw_metering = hw_metering;
    } else {
        driver->has_hw_metering = FALSE;
        driver->hw_metering = FALSE;
    }

    return 0;
}

void
JackAlsaDriver::alsa_driver_setup_io_function_pointers (alsa_driver_t *driver)
{
	if (SND_PCM_FORMAT_FLOAT_LE == driver->playback_sample_format) {
		if (driver->playback_interleaved) {
			driver->channel_copy = memcpy_interleave_d32_s32;
		} else {
			driver->channel_copy = memcpy_fake;
		}
		driver->read_via_copy = sample_move_floatLE_sSs;
		driver->write_via_copy = sample_move_dS_floatLE;
	} else {

		switch (driver->playback_sample_bytes) {
		case 2:
			if (driver->playback_interleaved) {
				driver->channel_copy = memcpy_interleave_d16_s16;
			} else {
				driver->channel_copy = memcpy_fake;
			}
			
			switch (driver->dither) {
			case Rectangular:
				jack_info("Rectangular dithering at 16 bits");
				driver->write_via_copy = driver->quirk_bswap?
                                        sample_move_dither_rect_d16_sSs:
                                        sample_move_dither_rect_d16_sS;
				break;
				
			case Triangular:
				jack_info("Triangular dithering at 16 bits");
				driver->write_via_copy = driver->quirk_bswap?
                                        sample_move_dither_tri_d16_sSs:
                                        sample_move_dither_tri_d16_sS;
				break;
				
			case Shaped:
				jack_info("Noise-shaped dithering at 16 bits");
				driver->write_via_copy = driver->quirk_bswap?
                                        sample_move_dither_shaped_d16_sSs:
                                        sample_move_dither_shaped_d16_sS;
				break;
				
			default:
				driver->write_via_copy = driver->quirk_bswap?
                                        sample_move_d16_sSs : 
        				sample_move_d16_sS;
				break;
			}
			break;
			
		case 3: /* NO DITHER */
			if (driver->playback_interleaved) {
				driver->channel_copy = memcpy_interleave_d24_s24;
			} else {
				driver->channel_copy = memcpy_fake;
			}
			
			driver->write_via_copy = driver->quirk_bswap?
				sample_move_d24_sSs: 
				sample_move_d24_sS;

			break;
									
	 	case 4: /* NO DITHER */
			if (driver->playback_interleaved) {
				driver->channel_copy = memcpy_interleave_d32_s32;
			} else {
				driver->channel_copy = memcpy_fake;
			}

			driver->write_via_copy = driver->quirk_bswap?
				sample_move_d32u24_sSs: 
				sample_move_d32u24_sS;
		    break;

		default:
			jack_error ("impossible sample width (%d) discovered!",
				    driver->playback_sample_bytes);
			exit (1);
		}
	}
	
	switch (driver->capture_sample_bytes) {
	case 2:
		driver->read_via_copy = driver->quirk_bswap?
			sample_move_dS_s16s: 
		        sample_move_dS_s16;
		break;
	case 3:
		driver->read_via_copy = driver->quirk_bswap?
			sample_move_dS_s24s: 
		        sample_move_dS_s24;
		break;
	case 4:
		driver->read_via_copy = driver->quirk_bswap?
		 	sample_move_dS_s32u24s: 
		        sample_move_dS_s32u24;
		break;
	}
}

int
JackAlsaDriver::alsa_driver_configure_stream (alsa_driver_t *driver, char *device_name,
        const char *stream_name,
        snd_pcm_t *handle,
        snd_pcm_hw_params_t *hw_params,
        snd_pcm_sw_params_t *sw_params,
        unsigned int *nperiodsp,
        unsigned long *nchns,
        unsigned long sample_width)
{
	int err, format;
	unsigned int frame_rate;
	snd_pcm_uframes_t stop_th;
	static struct {
		char Name[32];
		snd_pcm_format_t format;
		int swapped;
	} formats[] = {
 	    {"32bit float little-endian", SND_PCM_FORMAT_FLOAT_LE},
		{"32bit integer little-endian", SND_PCM_FORMAT_S32_LE, IS_LE},
		{"32bit integer big-endian", SND_PCM_FORMAT_S32_BE, IS_BE},
		{"24bit little-endian", SND_PCM_FORMAT_S24_3LE, IS_LE},
		{"24bit big-endian", SND_PCM_FORMAT_S24_3BE, IS_BE},
		{"16bit little-endian", SND_PCM_FORMAT_S16_LE, IS_LE},
		{"16bit big-endian", SND_PCM_FORMAT_S16_BE, IS_BE},
	};
#define NUMFORMATS (sizeof(formats)/sizeof(formats[0]))
#define FIRST_16BIT_FORMAT 5

	if ((err = snd_pcm_hw_params_any (handle, hw_params)) < 0)  {
		jack_error ("ALSA: no playback configurations available (%s)",
			    snd_strerror (err));
		return -1;
	}

	if ((err = snd_pcm_hw_params_set_periods_integer (handle, hw_params))
	    < 0) {
		jack_error ("ALSA: cannot restrict period size to integral"
			    " value.");
		return -1;
	}

	if ((err = snd_pcm_hw_params_set_access (handle, hw_params, SND_PCM_ACCESS_MMAP_NONINTERLEAVED)) < 0) {
		if ((err = snd_pcm_hw_params_set_access (handle, hw_params, SND_PCM_ACCESS_MMAP_INTERLEAVED)) < 0) {
			if ((err = snd_pcm_hw_params_set_access (
				     handle, hw_params,
				     SND_PCM_ACCESS_MMAP_COMPLEX)) < 0) {
				jack_error ("ALSA: mmap-based access is not possible"
					    " for the %s "
					    "stream of this audio interface",
					    stream_name);
				return -1;
			}
		}
	}
	
	format = (sample_width == 4) ? 0 : NUMFORMATS - 1;

	while (1) {
		if ((err = snd_pcm_hw_params_set_format (
			     handle, hw_params, formats[format].format)) < 0) {

			if ((sample_width == 4
			     ? format++ >= NUMFORMATS - 1
			     : format-- <= 0)) {
				jack_error ("Sorry. The audio interface \"%s\""
					    " doesn't support any of the"
					    " hardware sample formats that"
					    " JACK's alsa-driver can use.",
					    device_name);
				return -1;
			}
		} else {
			if (formats[format].swapped) {
				driver->quirk_bswap = 1;
			} else {
				driver->quirk_bswap = 0;
			}
			jack_info ("ALSA: final selected sample format for %s: %s", stream_name, formats[format].Name);
			break;
		}
	} 

	frame_rate = driver->frame_rate ;
	err = snd_pcm_hw_params_set_rate_near (handle, hw_params,
					       &frame_rate, NULL) ;
	driver->frame_rate = frame_rate ;
	if (err < 0) {
		jack_error ("ALSA: cannot set sample/frame rate to ld% for %s", driver->frame_rate,
			    stream_name);
		return -1;
	}
	if (!*nchns) {
		/*if not user-specified, try to find the maximum
		 * number of channels */
		unsigned int channels_max ;
		err = snd_pcm_hw_params_get_channels_max (hw_params,
							  &channels_max);
		*nchns = channels_max ;

		if (*nchns > 1024) { 

			/* the hapless user is an unwitting victim of
			   the "default" ALSA PCM device, which can
			   support up to 16 million channels. since
			   they can't be bothered to set up a proper
			   default device, limit the number of
			   channels for them to a sane default.
			*/

			jack_error (
"You appear to be using the ALSA software \"plug\" layer, probably\n"
"a result of using the \"default\" ALSA device. This is less\n"
"efficient than it could be. Consider using a hardware device\n"
"instead rather than using the plug layer. Usually the name of the\n"
"hardware device that corresponds to the first sound card is hw:0\n"
				);
			*nchns = 2;  
		}
	}				

	if ((err = snd_pcm_hw_params_set_channels (handle, hw_params,
						   *nchns)) < 0) {
		jack_error ("ALSA: cannot set channel count to %u for %s",
			    *nchns, stream_name);
		return -1;
	}
	
	if ((err = snd_pcm_hw_params_set_period_size (handle, hw_params,
						      driver->frames_per_cycle,
						      0))
	    < 0) {
		jack_error ("ALSA: cannot set period size to ld% frames for %s", driver->frames_per_cycle,
			    stream_name);
		return -1;
	}

	*nperiodsp = driver->user_nperiods;
	snd_pcm_hw_params_set_periods_min (handle, hw_params, nperiodsp, NULL);
	if (*nperiodsp < driver->user_nperiods)
		*nperiodsp = driver->user_nperiods;
	if (snd_pcm_hw_params_set_periods_near (handle, hw_params,
						nperiodsp, NULL) < 0) {
		jack_error ("ALSA: cannot set number of periods to %u for %s",
			    *nperiodsp, stream_name);
		return -1;
	}

	if (*nperiodsp < driver->user_nperiods) {
		jack_error ("ALSA: got smaller periods %u than %u for %s",
			    *nperiodsp, (unsigned int) driver->user_nperiods,
			    stream_name);
		return -1;
	}
	jack_info ("ALSA: use %d periods for %s", *nperiodsp, stream_name);
#if 0	
	if (!jack_power_of_two(driver->frames_per_cycle)) {
		jack_error("JACK: frames must be a power of two "
			   "(64, 512, 1024, ...)\n");
		return -1;
	}
#endif

	if ((err = snd_pcm_hw_params_set_buffer_size (handle, hw_params,
						      *nperiodsp *
						      driver->frames_per_cycle))
	    < 0) {
		jack_error ("ALSA: cannot set buffer length to ld% for %s",
			    *nperiodsp * driver->frames_per_cycle,
			    stream_name);
		return -1;
	}

	if ((err = snd_pcm_hw_params (handle, hw_params)) < 0) {
		jack_error ("ALSA: cannot set hardware parameters for %s",
			    stream_name);
		return -1;
	}

	snd_pcm_sw_params_current (handle, sw_params);

	if ((err = snd_pcm_sw_params_set_start_threshold (handle, sw_params,
							  0U)) < 0) {
		jack_error ("ALSA: cannot set start mode for %s", stream_name);
		return -1;
	}

	stop_th = *nperiodsp * driver->frames_per_cycle;
	if (driver->soft_mode) {
		stop_th = (snd_pcm_uframes_t)-1;
	}
	
	if ((err = snd_pcm_sw_params_set_stop_threshold (
		     handle, sw_params, stop_th)) < 0) {
		jack_error ("ALSA: cannot set stop mode for %s",
			    stream_name);
		return -1;
	}

	if ((err = snd_pcm_sw_params_set_silence_threshold (
		     handle, sw_params, 0)) < 0) {
		jack_error ("ALSA: cannot set silence threshold for %s",
			    stream_name);
		return -1;
	}

#if 0
	jack_info ("set silence size to %lu * %lu = %lu",
		 driver->frames_per_cycle, *nperiodsp,
		 driver->frames_per_cycle * *nperiodsp);

	if ((err = snd_pcm_sw_params_set_silence_size (
		     handle, sw_params,
		     driver->frames_per_cycle * *nperiodsp)) < 0) {
		jack_error ("ALSA: cannot set silence size for %s",
			    stream_name);
		return -1;
	}
#endif

	if (handle == driver->playback_handle)
		err = snd_pcm_sw_params_set_avail_min (
			handle, sw_params,
			driver->frames_per_cycle
			* (*nperiodsp - driver->user_nperiods + 1));
	else
		err = snd_pcm_sw_params_set_avail_min (
			handle, sw_params, driver->frames_per_cycle);
			
	if (err < 0) {
		jack_error ("ALSA: cannot set avail min for %s", stream_name);
		return -1;
	}

	if ((err = snd_pcm_sw_params (handle, sw_params)) < 0) {
		jack_error ("ALSA: cannot set software parameters for %s\n",
			    stream_name);
		return -1;
	}

	return 0;
}

int
JackAlsaDriver::alsa_driver_set_parameters (alsa_driver_t *driver,
        jack_nframes_t frames_per_cycle,
        jack_nframes_t user_nperiods,
        jack_nframes_t rate)
{
    int dir;
    snd_pcm_uframes_t p_period_size = 0;
    snd_pcm_uframes_t c_period_size = 0;
    channel_t chn;
    unsigned int pr = 0;
    unsigned int cr = 0;
    int err;

    driver->frame_rate = rate;
    driver->frames_per_cycle = frames_per_cycle;
    driver->user_nperiods = user_nperiods;


    /* // steph
    jack_info ("configuring for %" PRIu32 "Hz, period = %"
		 PRIu32 " frames (%.1f ms), buffer = %" PRIu32 " periods",
		 rate, frames_per_cycle, (((float)frames_per_cycle / (float) rate) * 1000.0f), user_nperiods);
    */

    if (driver->capture_handle) {
        if (alsa_driver_configure_stream (
                    driver,
                    driver->alsa_name_capture,
                    "capture",
                    driver->capture_handle,
                    driver->capture_hw_params,
                    driver->capture_sw_params,
                    &driver->capture_nperiods,
                    (long unsigned int*)&driver->capture_nchannels,
                    driver->capture_sample_bytes)) {
            jack_error ("ALSA: cannot configure capture channel");
            return -1;
        }
    }

    if (driver->playback_handle) {
        if (alsa_driver_configure_stream (
                    driver,
                    driver->alsa_name_playback,
                    "playback",
                    driver->playback_handle,
                    driver->playback_hw_params,
                    driver->playback_sw_params,
                    &driver->playback_nperiods,
                    (long unsigned int*)&driver->playback_nchannels,
                    driver->playback_sample_bytes)) {
            jack_error ("ALSA: cannot configure playback channel");
            return -1;
        }
    }

    /* check the rate, since thats rather important */

    if (driver->playback_handle) {
        snd_pcm_hw_params_get_rate (driver->playback_hw_params,
                                    &pr, &dir);
    }

    if (driver->capture_handle) {
        snd_pcm_hw_params_get_rate (driver->capture_hw_params,
                                    &cr, &dir);
    }

    if (driver->capture_handle && driver->playback_handle) {
        if (cr != pr) {
            jack_error ("playback and capture sample rates do "
                        "not match (%d vs. %d)", pr, cr);
        }

        /* only change if *both* capture and playback rates
         * don't match requested certain hardware actually
         * still works properly in full-duplex with slightly
         * different rate values between adc and dac
         */
        if (cr != driver->frame_rate && pr != driver->frame_rate) {
            jack_error ("sample rate in use (%d Hz) does not "
                        "match requested rate (%d Hz)",
                        cr, driver->frame_rate);
            driver->frame_rate = cr;
        }

    } else if (driver->capture_handle && cr != driver->frame_rate) {
        jack_error ("capture sample rate in use (%d Hz) does not "
                    "match requested rate (%d Hz)",
                    cr, driver->frame_rate);
        driver->frame_rate = cr;
    } else if (driver->playback_handle && pr != driver->frame_rate) {
        jack_error ("playback sample rate in use (%d Hz) does not "
                    "match requested rate (%d Hz)",
                    pr, driver->frame_rate);
        driver->frame_rate = pr;
    }


    /* check the fragment size, since thats non-negotiable */

    if (driver->playback_handle) {
        snd_pcm_access_t access;

        err = snd_pcm_hw_params_get_period_size (
                  driver->playback_hw_params, &p_period_size, &dir);
        err = snd_pcm_hw_params_get_format (
                  driver->playback_hw_params,
                  &(driver->playback_sample_format));
        err = snd_pcm_hw_params_get_access (driver->playback_hw_params,
                                            &access);
        driver->playback_interleaved =
            (access == SND_PCM_ACCESS_MMAP_INTERLEAVED)
            || (access == SND_PCM_ACCESS_MMAP_COMPLEX);

        if (p_period_size != driver->frames_per_cycle) {
            /*
            jack_error ("alsa_pcm: requested an interrupt every %"
            	    PRIu32
            	    " frames but got %u frames for playback",
            	    driver->frames_per_cycle, p_period_size);
            	    */
            return -1;
        }
    }

    if (driver->capture_handle) {
        snd_pcm_access_t access;

        err = snd_pcm_hw_params_get_period_size (
                  driver->capture_hw_params, &c_period_size, &dir);
        err = snd_pcm_hw_params_get_format (
                  driver->capture_hw_params,
                  &(driver->capture_sample_format));
        err = snd_pcm_hw_params_get_access (driver->capture_hw_params,
                                            &access);
        driver->capture_interleaved =
            (access == SND_PCM_ACCESS_MMAP_INTERLEAVED)
            || (access == SND_PCM_ACCESS_MMAP_COMPLEX);


        if (c_period_size != driver->frames_per_cycle) {
            /* // steph
            jack_error ("alsa_pcm: requested an interrupt every %"
            	    PRIu32
            	    " frames but got %uc frames for capture",
            	    driver->frames_per_cycle, p_period_size);
            */
            return -1;
        }
    }

    driver->playback_sample_bytes =
        snd_pcm_format_physical_width (driver->playback_sample_format)
        / 8;
    driver->capture_sample_bytes =
        snd_pcm_format_physical_width (driver->capture_sample_format)
        / 8;

    if (driver->playback_handle) {
        switch (driver->playback_sample_format) {
           case SND_PCM_FORMAT_FLOAT_LE:
            case SND_PCM_FORMAT_S32_LE:
            case SND_PCM_FORMAT_S24_3LE:
            case SND_PCM_FORMAT_S24_3BE:
            case SND_PCM_FORMAT_S16_LE:
            case SND_PCM_FORMAT_S32_BE:
            case SND_PCM_FORMAT_S16_BE:
                break;

            default:
                jack_error ("programming error: unhandled format "
                            "type for playback");
                exit (1);
        }
    }

    if (driver->capture_handle) {
        switch (driver->capture_sample_format) {
           case SND_PCM_FORMAT_FLOAT_LE:
            case SND_PCM_FORMAT_S32_LE:
            case SND_PCM_FORMAT_S24_3LE:
            case SND_PCM_FORMAT_S24_3BE:
            case SND_PCM_FORMAT_S16_LE:
            case SND_PCM_FORMAT_S32_BE:
            case SND_PCM_FORMAT_S16_BE:
                break;

            default:
                jack_error ("programming error: unhandled format "
                            "type for capture");
                exit (1);
        }
    }

    if (driver->playback_interleaved) {
        const snd_pcm_channel_area_t *my_areas;
        snd_pcm_uframes_t offset, frames;
        if (snd_pcm_mmap_begin(driver->playback_handle,
                               &my_areas, &offset, &frames) < 0) {
            jack_error ("ALSA: %s: mmap areas info error",
                        driver->alsa_name_playback);
            return -1;
        }
        driver->interleave_unit =
            snd_pcm_format_physical_width (
                driver->playback_sample_format) / 8;
    } else {
        driver->interleave_unit = 0;  /* NOT USED */
    }

    if (driver->capture_interleaved) {
        const snd_pcm_channel_area_t *my_areas;
        snd_pcm_uframes_t offset, frames;
        if (snd_pcm_mmap_begin(driver->capture_handle,
                               &my_areas, &offset, &frames) < 0) {
            jack_error ("ALSA: %s: mmap areas info error",
                        driver->alsa_name_capture);
            return -1;
        }
    }

    if (driver->playback_nchannels > driver->capture_nchannels) {
        driver->max_nchannels = driver->playback_nchannels;
        driver->user_nchannels = driver->capture_nchannels;
    } else {
        driver->max_nchannels = driver->capture_nchannels;
        driver->user_nchannels = driver->playback_nchannels;
    }

    alsa_driver_setup_io_function_pointers (driver);

    /* Allocate and initialize structures that rely on the
       channels counts.

       Set up the bit pattern that is used to record which
       channels require action on every cycle. any bits that are
       not set after the engine's process() call indicate channels
       that potentially need to be silenced.
    */

    bitset_create (&driver->channels_done, driver->max_nchannels);
    bitset_create (&driver->channels_not_done, driver->max_nchannels);

    if (driver->playback_handle) {
        driver->playback_addr = (char **)
                                malloc (sizeof (char *) * driver->playback_nchannels);
        memset (driver->playback_addr, 0,
                sizeof (char *) * driver->playback_nchannels);
        driver->playback_interleave_skip = (unsigned long *)
                                           malloc (sizeof (unsigned long *) * driver->playback_nchannels);
        memset (driver->playback_interleave_skip, 0,
                sizeof (unsigned long *) * driver->playback_nchannels);
        driver->silent = (unsigned long *)
                         malloc (sizeof (unsigned long)
                                 * driver->playback_nchannels);

        for (chn = 0; chn < driver->playback_nchannels; chn++) {
            driver->silent[chn] = 0;
        }

        for (chn = 0; chn < driver->playback_nchannels; chn++) {
            bitset_add (driver->channels_done, chn);
        }

        driver->dither_state = (dither_state_t *)
                               calloc ( driver->playback_nchannels,
                                        sizeof (dither_state_t));
    }

    if (driver->capture_handle) {
        driver->capture_addr = (char **)
                               malloc (sizeof (char *) * driver->capture_nchannels);
        memset (driver->capture_addr, 0,
                sizeof (char *) * driver->capture_nchannels);
        driver->capture_interleave_skip = (unsigned long *)
                                          malloc (sizeof (unsigned long *) * driver->capture_nchannels);
        memset (driver->capture_interleave_skip, 0,
                sizeof (unsigned long *) * driver->capture_nchannels);
    }

    driver->clock_sync_data = (ClockSyncStatus *)
                              malloc (sizeof (ClockSyncStatus) * driver->max_nchannels);

    driver->period_usecs =
        (jack_time_t) floor ((((float) driver->frames_per_cycle) /
                              driver->frame_rate) * 1000000.0f);
    driver->poll_timeout = (int) floor (1.5f * driver->period_usecs);

    // steph
    /*
    if (driver->engine) {
    	driver->engine->set_buffer_size (driver->engine,
    					 driver->frames_per_cycle);
    }
    */
    return 0;
}

int
JackAlsaDriver::alsa_driver_reset_parameters (alsa_driver_t *driver,
        jack_nframes_t frames_per_cycle,
        jack_nframes_t user_nperiods,
        jack_nframes_t rate)
{
    /* XXX unregister old ports ? */
    alsa_driver_release_channel_dependent_memory (driver);
    return alsa_driver_set_parameters (driver,
                                       frames_per_cycle,
                                       user_nperiods, rate);
}

int
JackAlsaDriver::alsa_driver_get_channel_addresses (alsa_driver_t *driver,
        snd_pcm_uframes_t *capture_avail,
        snd_pcm_uframes_t *playback_avail,
        snd_pcm_uframes_t *capture_offset,
        snd_pcm_uframes_t *playback_offset)
{
    unsigned long err;
    channel_t chn;

    if (capture_avail) {
        if ((err = snd_pcm_mmap_begin (
                       driver->capture_handle, &driver->capture_areas,
                       (snd_pcm_uframes_t *) capture_offset,
                       (snd_pcm_uframes_t *) capture_avail)) < 0) {
            jack_error ("ALSA: %s: mmap areas info error",
                        driver->alsa_name_capture);
            return -1;
        }

        for (chn = 0; chn < driver->capture_nchannels; chn++) {
            const snd_pcm_channel_area_t *a =
                &driver->capture_areas[chn];
            driver->capture_addr[chn] = (char *) a->addr
                                        + ((a->first + a->step * *capture_offset) / 8);
            driver->capture_interleave_skip[chn] = (unsigned long ) (a->step / 8);
        }
    }

    if (playback_avail) {
        if ((err = snd_pcm_mmap_begin (
                       driver->playback_handle, &driver->playback_areas,
                       (snd_pcm_uframes_t *) playback_offset,
                       (snd_pcm_uframes_t *) playback_avail)) < 0) {
            jack_error ("ALSA: %s: mmap areas info error ",
                        driver->alsa_name_playback);
            return -1;
        }

        for (chn = 0; chn < driver->playback_nchannels; chn++) {
            const snd_pcm_channel_area_t *a =
                &driver->playback_areas[chn];
            driver->playback_addr[chn] = (char *) a->addr
                                         + ((a->first + a->step * *playback_offset) / 8);
            driver->playback_interleave_skip[chn] = (unsigned long ) (a->step / 8);
        }
    }

    return 0;
}

int
JackAlsaDriver::alsa_driver_start (alsa_driver_t *driver)
{
    int err;
    snd_pcm_uframes_t poffset, pavail;
    channel_t chn;

    driver->poll_last = 0;
    driver->poll_next = 0;

    if (driver->playback_handle) {
        if ((err = snd_pcm_prepare (driver->playback_handle)) < 0) {
            jack_error ("ALSA: prepare error for playback on "
                        "\"%s\" (%s)", driver->alsa_name_playback,
                        snd_strerror(err));
            return -1;
        }
    }

    if ((driver->capture_handle && driver->capture_and_playback_not_synced)
            || !driver->playback_handle) {
        if ((err = snd_pcm_prepare (driver->capture_handle)) < 0) {
            jack_error ("ALSA: prepare error for capture on \"%s\""
                        " (%s)", driver->alsa_name_capture,
                        snd_strerror(err));
            return -1;
        }
    }

    if (driver->hw_monitoring) {
        if (driver->input_monitor_mask || driver->all_monitor_in) {
            if (driver->all_monitor_in) {
                driver->hw->set_input_monitor_mask (driver->hw, ~0U);
            } else {
                driver->hw->set_input_monitor_mask (
                    driver->hw, driver->input_monitor_mask);
            }
        } else {
            driver->hw->set_input_monitor_mask (driver->hw,
                                                driver->input_monitor_mask);
        }
    }

    if (driver->playback_handle) {
        driver->playback_nfds =
            snd_pcm_poll_descriptors_count (driver->playback_handle);
    } else {
        driver->playback_nfds = 0;
    }

    if (driver->capture_handle) {
        driver->capture_nfds =
            snd_pcm_poll_descriptors_count (driver->capture_handle);
    } else {
        driver->capture_nfds = 0;
    }

    if (driver->pfd) {
        free (driver->pfd);
    }

    driver->pfd = (struct pollfd *)
                  malloc (sizeof (struct pollfd) *
                          (driver->playback_nfds + driver->capture_nfds + 2));

    if (driver->midi && !driver->xrun_recovery)
        (driver->midi->start)(driver->midi);

    if (driver->playback_handle) {
        /* fill playback buffer with zeroes, and mark
           all fragments as having data.
        */

        pavail = snd_pcm_avail_update (driver->playback_handle);

        if (pavail !=
                driver->frames_per_cycle * driver->playback_nperiods) {
            jack_error ("ALSA: full buffer not available at start");
            return -1;
        }

        if (alsa_driver_get_channel_addresses (driver,
                                               0, &pavail, 0, &poffset)) {
            return -1;
        }

        /* XXX this is cheating. ALSA offers no guarantee that
           we can access the entire buffer at any one time. It
           works on most hardware tested so far, however, buts
           its a liability in the long run. I think that
           alsa-lib may have a better function for doing this
           here, where the goal is to silence the entire
           buffer.
        */

        for (chn = 0; chn < driver->playback_nchannels; chn++) {
            alsa_driver_silence_on_channel (
                driver, chn,
                driver->user_nperiods
                * driver->frames_per_cycle);
        }

        snd_pcm_mmap_commit (driver->playback_handle, poffset,
                             driver->user_nperiods
                             * driver->frames_per_cycle);

        if ((err = snd_pcm_start (driver->playback_handle)) < 0) {
            jack_error ("ALSA: could not start playback (%s)",
                        snd_strerror (err));
            return -1;
        }
    }

    if ((driver->capture_handle && driver->capture_and_playback_not_synced)
            || !driver->playback_handle) {
        if ((err = snd_pcm_start (driver->capture_handle)) < 0) {
            jack_error ("ALSA: could not start capture (%s)",
                        snd_strerror (err));
            return -1;
        }
    }

    return 0;
}

int
JackAlsaDriver::alsa_driver_stop (alsa_driver_t *driver)
{
    int err;
    //JSList* node;
    //int chn;

    /* silence all capture port buffers, because we might
       be entering offline mode.
    */

    // steph
    /*
    for (chn = 0, node = driver->capture_ports; node;
         node = jack_slist_next (node), chn++) {

    	jack_port_t* port;
    	char* buf;
    	jack_nframes_t nframes = driver->engine->control->buffer_size;

    	port = (jack_port_t *) node->data;
    	buf = jack_port_get_buffer (port, nframes);
    	memset (buf, 0, sizeof (jack_default_audio_sample_t) * nframes);
    }
    */

    for (int i = 0; i < fPlaybackChannels; i++) {
        jack_default_audio_sample_t* buf =
            (jack_default_audio_sample_t*)fGraphManager->GetBuffer(fPlaybackPortList[i], fEngineControl->fBufferSize);
        memset (buf, 0, sizeof (jack_default_audio_sample_t) * fEngineControl->fBufferSize);
    }

    if (driver->playback_handle) {
        if ((err = snd_pcm_drop (driver->playback_handle)) < 0) {
            jack_error ("ALSA: channel flush for playback "
                        "failed (%s)", snd_strerror (err));
            return -1;
        }
    }

    if (!driver->playback_handle
            || driver->capture_and_playback_not_synced) {
        if (driver->capture_handle) {
            if ((err = snd_pcm_drop (driver->capture_handle)) < 0) {
                jack_error ("ALSA: channel flush for "
                            "capture failed (%s)",
                            snd_strerror (err));
                return -1;
            }
        }
    }

    if (driver->hw_monitoring) {
        driver->hw->set_input_monitor_mask (driver->hw, 0);
    }

    if (driver->midi && !driver->xrun_recovery)
        (driver->midi->stop)(driver->midi);

    return 0;
}

int
JackAlsaDriver::alsa_driver_restart (alsa_driver_t *driver)
{
    int res;
    
    driver->xrun_recovery = 1;
    if ((res = Stop()) == 0)
        res = Start();
    driver->xrun_recovery = 0;

    if (res && driver->midi)
	(driver->midi->stop)(driver->midi);

    return res;
}

int
JackAlsaDriver::alsa_driver_xrun_recovery (alsa_driver_t *driver, float *delayed_usecs)
{
    snd_pcm_status_t *status;
    int res;

    jack_error("alsa_driver_xrun_recovery");

    snd_pcm_status_alloca(&status);

    if (driver->capture_handle) {
        if ((res = snd_pcm_status(driver->capture_handle, status))
                < 0) {
            jack_error("status error: %s", snd_strerror(res));
        }
    } else {
        if ((res = snd_pcm_status(driver->playback_handle, status))
                < 0) {
            jack_error("status error: %s", snd_strerror(res));
        }
    }

    if (snd_pcm_status_get_state(status) == SND_PCM_STATE_XRUN
            && driver->process_count > XRUN_REPORT_DELAY) {
        struct timeval now, diff, tstamp;
        driver->xrun_count++;
        snd_pcm_status_get_tstamp(status,&now); 
        snd_pcm_status_get_trigger_tstamp(status, &tstamp);
        timersub(&now, &tstamp, &diff);
        *delayed_usecs = diff.tv_sec * 1000000.0 + diff.tv_usec;
        jack_error("\n\n**** alsa_pcm: xrun of at least %.3f msecs\n\n", *delayed_usecs / 1000.0);
    }

    if (alsa_driver_restart (driver)) {
        return -1;
    }
    return 0;
}

void
JackAlsaDriver::alsa_driver_silence_untouched_channels (alsa_driver_t *driver,
        jack_nframes_t nframes)
{
    channel_t chn;
    jack_nframes_t buffer_frames =
        driver->frames_per_cycle * driver->playback_nperiods;

    for (chn = 0; chn < driver->playback_nchannels; chn++) {
        if (bitset_contains (driver->channels_not_done, chn)) {
            if (driver->silent[chn] < buffer_frames) {
                alsa_driver_silence_on_channel_no_mark (
                    driver, chn, nframes);
                driver->silent[chn] += nframes;
            }
        }
    }
}

static int under_gdb = FALSE;

jack_nframes_t
JackAlsaDriver::alsa_driver_wait (alsa_driver_t *driver, int extra_fd, int *status, float
                                  *delayed_usecs)
{
	snd_pcm_sframes_t avail = 0;
	snd_pcm_sframes_t capture_avail = 0;
	snd_pcm_sframes_t playback_avail = 0;
	int xrun_detected = FALSE;
	int need_capture;
	int need_playback;
	unsigned int i;
	jack_time_t poll_enter;
	jack_time_t poll_ret = 0;

	*status = -1;
	*delayed_usecs = 0;

	need_capture = driver->capture_handle ? 1 : 0;

	if (extra_fd >= 0) {
		need_playback = 0;
	} else {
		need_playback = driver->playback_handle ? 1 : 0;
	}

  again:
	
	while (need_playback || need_capture) {

		int poll_result;
		unsigned int ci = 0;
		unsigned int nfds;
		unsigned short revents;

		nfds = 0;

		if (need_playback) {
			snd_pcm_poll_descriptors (driver->playback_handle,
						  &driver->pfd[0],
						  driver->playback_nfds);
			nfds += driver->playback_nfds;
		}
		
		if (need_capture) {
			snd_pcm_poll_descriptors (driver->capture_handle,
						  &driver->pfd[nfds],
						  driver->capture_nfds);
			ci = nfds;
			nfds += driver->capture_nfds;
		}

		/* ALSA doesn't set POLLERR in some versions of 0.9.X */
		
		for (i = 0; i < nfds; i++) {
			driver->pfd[i].events |= POLLERR;
		}

		if (extra_fd >= 0) {
			driver->pfd[nfds].fd = extra_fd;
			driver->pfd[nfds].events =
				POLLIN|POLLERR|POLLHUP|POLLNVAL;
			nfds++;
		}

		poll_enter = jack_get_microseconds ();

		if (poll_enter > driver->poll_next) {
			/*
			 * This processing cycle was delayed past the
			 * next due interrupt!  Do not account this as
			 * a wakeup delay:
			 */
			driver->poll_next = 0;
			driver->poll_late++;
		}

		poll_result = poll (driver->pfd, nfds, driver->poll_timeout);
		if (poll_result < 0) {

			if (errno == EINTR) {
				jack_info ("poll interrupt");
				// this happens mostly when run
				// under gdb, or when exiting due to a signal
				if (under_gdb) {
					goto again;
				}
				*status = -2;
				return 0;
			}
			
			jack_error ("ALSA: poll call failed (%s)",
				    strerror (errno));
			*status = -3;
			return 0;
			
		}

		poll_ret = jack_get_microseconds ();

		if (extra_fd < 0) {
			if (driver->poll_next && poll_ret > driver->poll_next) {
				*delayed_usecs = poll_ret - driver->poll_next;
			} 
			driver->poll_last = poll_ret;
			driver->poll_next = poll_ret + driver->period_usecs;
			// steph
			/*
			driver->engine->transport_cycle_start (driver->engine, 
							       poll_ret);
			*/
		}

#ifdef DEBUG_WAKEUP
		jack_info ("%" PRIu64 ": checked %d fds, %" PRIu64
			 " usecs since poll entered", poll_ret, nfds,
			 poll_ret - poll_enter);
#endif

		/* check to see if it was the extra FD that caused us
		 * to return from poll */

		if (extra_fd >= 0) {

			if (driver->pfd[nfds-1].revents == 0) {
				/* we timed out on the extra fd */

				*status = -4;
				return -1;
			} 

			/* if POLLIN was the only bit set, we're OK */

			*status = 0;
			return (driver->pfd[nfds-1].revents == POLLIN) ? 0 : -1;
		}

		if (need_playback) {
			if (snd_pcm_poll_descriptors_revents
			    (driver->playback_handle, &driver->pfd[0],
			     driver->playback_nfds, &revents) < 0) {
				jack_error ("ALSA: playback revents failed");
				*status = -6;
				return 0;
			}

			if (revents & POLLERR) {
				xrun_detected = TRUE;
			}

			if (revents & POLLOUT) {
				need_playback = 0;
#ifdef DEBUG_WAKEUP
				jack_info ("%" PRIu64
					 " playback stream ready",
					 poll_ret);
#endif
			}
		}

		if (need_capture) {
			if (snd_pcm_poll_descriptors_revents
			    (driver->capture_handle, &driver->pfd[ci],
			     driver->capture_nfds, &revents) < 0) {
				jack_error ("ALSA: capture revents failed");
				*status = -6;
				return 0;
			}

			if (revents & POLLERR) {
				xrun_detected = TRUE;
			}

			if (revents & POLLIN) {
				need_capture = 0;
#ifdef DEBUG_WAKEUP
				jack_info ("%" PRIu64
					 " capture stream ready",
					 poll_ret);
#endif
			}
		}
		
		if (poll_result == 0) {
			jack_error ("ALSA: poll time out, polled for %ld usecs",
				    poll_ret - poll_enter);
			*status = -5;
			return 0;
		}		

	}

	if (driver->capture_handle) {
		if ((capture_avail = snd_pcm_avail_update (
			     driver->capture_handle)) < 0) {
			if (capture_avail == -EPIPE) {
				xrun_detected = TRUE;
			} else {
				jack_error ("unknown ALSA avail_update return"
					    " value (%u)", capture_avail);
			}
		}
	} else {
		/* odd, but see min() computation below */
		capture_avail = INT_MAX; 
	}

	if (driver->playback_handle) {
		if ((playback_avail = snd_pcm_avail_update (
			     driver->playback_handle)) < 0) {
			if (playback_avail == -EPIPE) {
				xrun_detected = TRUE;
			} else {
				jack_error ("unknown ALSA avail_update return"
					    " value (%u)", playback_avail);
			}
		}
	} else {
		/* odd, but see min() computation below */
		playback_avail = INT_MAX; 
	}

	if (xrun_detected) {
		*status = alsa_driver_xrun_recovery (driver, delayed_usecs);
		return 0;
	}

	*status = 0;
	driver->last_wait_ust = poll_ret;

	avail = capture_avail < playback_avail ? capture_avail : playback_avail;

#ifdef DEBUG_WAKEUP
	jack_info ("wakeup complete, avail = %lu, pavail = %lu "
		 "cavail = %lu",
		 avail, playback_avail, capture_avail);
#endif

	/* mark all channels not done for now. read/write will change this */

	bitset_copy (driver->channels_not_done, driver->channels_done);

	/* constrain the available count to the nearest (round down) number of
	   periods.
	*/

	return avail - (avail % driver->frames_per_cycle);
}


int JackAlsaDriver::SetBufferSize(jack_nframes_t buffer_size)
{
    jack_log("JackAlsaDriver::SetBufferSize %ld", buffer_size);
    int res = alsa_driver_reset_parameters((alsa_driver_t *)fDriver, buffer_size,
                                           ((alsa_driver_t *)fDriver)->user_nperiods,
                                           ((alsa_driver_t *)fDriver)->frame_rate);

    if (res == 0) { // update fEngineControl and fGraphManager
        JackAudioDriver::SetBufferSize(buffer_size); // never fails
    } else {
        alsa_driver_reset_parameters((alsa_driver_t *)fDriver, fEngineControl->fBufferSize,
                                     ((alsa_driver_t *)fDriver)->user_nperiods,
                                     ((alsa_driver_t *)fDriver)->frame_rate);
    }

    return res;
}

int
JackAlsaDriver::alsa_driver_read (alsa_driver_t *driver, jack_nframes_t nframes)
{
    snd_pcm_sframes_t contiguous;
    snd_pcm_sframes_t nread;
    snd_pcm_sframes_t offset;
    jack_nframes_t orig_nframes;
    jack_default_audio_sample_t* buf;
    //channel_t chn;
    //JSList *node;
    //jack_port_t* port;
    int err;

    // steph
    /*
    if (!driver->capture_handle || driver->engine->freewheeling) {
    	return 0;
    }
    */

    if (nframes > driver->frames_per_cycle) {
        return -1;
    }

    if (driver->midi)
        (driver->midi->read)(driver->midi, nframes);

    if (!driver->capture_handle) {
        return 0;
    }
   
    nread = 0;
    contiguous = 0;
    orig_nframes = nframes;

    while (nframes) {

        contiguous = nframes;

        if (alsa_driver_get_channel_addresses (
                    driver,
                    (snd_pcm_uframes_t *) &contiguous,
                    (snd_pcm_uframes_t *) 0,
                    (snd_pcm_uframes_t *)&offset, 0) < 0) {
            return -1;
        }

        // steph
        for (int chn = 0; chn < fCaptureChannels; chn++) {
            if (fGraphManager->GetConnectionsNum(fCapturePortList[chn]) > 0) {
                buf = (jack_default_audio_sample_t*)fGraphManager->GetBuffer(fCapturePortList[chn], orig_nframes);
                alsa_driver_read_from_channel (driver, chn, buf + nread, contiguous);
            }
        }

        /* // steph
        for (chn = 0, node = driver->capture_ports; node;
             node = jack_slist_next (node), chn++) {
        	
        	port = (jack_port_t *) node->data;
        	
        	if (!jack_port_connected (port)) {
        		// no-copy optimization 
        		continue;
        	}
        	buf = jack_port_get_buffer (port, orig_nframes);
        	alsa_driver_read_from_channel (driver, chn,
        		buf + nread, contiguous);
        }
        */

        if ((err = snd_pcm_mmap_commit (driver->capture_handle,
                                        offset, contiguous)) < 0) {
            // steph
            // jack_error ("ALSA: could not complete read of %"
            //	PRIu32 " frames: error = %d\n", contiguous, err);
            jack_error ("ALSA: could not complete read of %d frames: error = %d", contiguous, err);
            return -1;
        }

        nframes -= contiguous;
        nread += contiguous;
    }

    return 0;
}

int
JackAlsaDriver::alsa_driver_write (alsa_driver_t* driver, jack_nframes_t nframes)
{
    //channel_t chn;
    //JSList *node;
    //JSList *mon_node;
    jack_default_audio_sample_t* buf;
    jack_default_audio_sample_t* monbuf;
    jack_nframes_t orig_nframes;
    snd_pcm_sframes_t nwritten;
    snd_pcm_sframes_t contiguous;
    snd_pcm_sframes_t offset;
    JackPort* port;
    //jack_port_t *port;
    int err;

    driver->process_count++;

    // steph
    /*
    if (!driver->playback_handle || driver->engine->freewheeling) {
    	return 0;
    }
    */
    if (!driver->playback_handle) {
        return 0;
    }

    if (nframes > driver->frames_per_cycle) {
        return -1;
    }

    if (driver->midi)
        (driver->midi->write)(driver->midi, nframes);

    nwritten = 0;
    contiguous = 0;
    orig_nframes = nframes;

    /* check current input monitor request status */

    driver->input_monitor_mask = 0;

    // steph
    /*
    for (chn = 0, node = driver->capture_ports; node;
         node = jack_slist_next (node), chn++) {
    	if (((jack_port_t *) node->data)->shared->monitor_requests) {
    		driver->input_monitor_mask |= (1<<chn);
    	}
    }
    */
    for (int chn = 0; chn < fCaptureChannels; chn++) {
        port = fGraphManager->GetPort(fCapturePortList[chn]);
        if (port->MonitoringInput()) {
            driver->input_monitor_mask |= (1 << chn);
        }
    }

    if (driver->hw_monitoring) {
        if ((driver->hw->input_monitor_mask
                != driver->input_monitor_mask)
                && !driver->all_monitor_in) {
            driver->hw->set_input_monitor_mask (
                driver->hw, driver->input_monitor_mask);
        }
    }

    while (nframes) {

        contiguous = nframes;

        if (alsa_driver_get_channel_addresses (
                    driver,
                    (snd_pcm_uframes_t *) 0,
                    (snd_pcm_uframes_t *) &contiguous,
                    0, (snd_pcm_uframes_t *)&offset) < 0) {
            return -1;
        }

        // steph
        for (int chn = 0; chn < fPlaybackChannels; chn++) {
            // Ouput ports
            if (fGraphManager->GetConnectionsNum(fPlaybackPortList[chn]) > 0) {
                buf = (jack_default_audio_sample_t*)fGraphManager->GetBuffer(fPlaybackPortList[chn], orig_nframes);
                alsa_driver_write_to_channel (driver, chn, buf + nwritten, contiguous);
                // Monitor ports
                if (fWithMonitorPorts && fGraphManager->GetConnectionsNum(fMonitorPortList[chn]) > 0) {
                    monbuf = (jack_default_audio_sample_t*)fGraphManager->GetBuffer(fMonitorPortList[chn], orig_nframes);
                    memcpy(monbuf + nwritten, buf + nwritten, contiguous * sizeof(jack_default_audio_sample_t));
                }
            }
        }

        /*
        for (chn = 0, node = driver->playback_ports, mon_node=driver->monitor_ports;
             node;
             node = jack_slist_next (node), chn++) {

        	port = (jack_port_t *) node->data;

        	if (!jack_port_connected (port)) {
        		continue;
        	}
        	buf = jack_port_get_buffer (port, orig_nframes);
        	alsa_driver_write_to_channel (driver, chn,
        		buf + nwritten, contiguous);

        	if (mon_node) {
        		port = (jack_port_t *) mon_node->data;
        		if (!jack_port_connected (port)) {
        			continue;
        		}
        		monbuf = jack_port_get_buffer (port, orig_nframes);
        		memcpy (monbuf + nwritten, buf + nwritten, contiguous * sizeof(jack_default_audio_sample_t));
        		mon_node = jack_slist_next (mon_node);				
        	}
        }
        */

        if (!bitset_empty (driver->channels_not_done)) {
            alsa_driver_silence_untouched_channels (driver,
                                                    contiguous);
        }

        if ((err = snd_pcm_mmap_commit (driver->playback_handle,
                                        offset, contiguous)) < 0) {
            // steph
            // jack_error ("ALSA: could not complete playback of %"
            //	PRIu32 " frames: error = %d", contiguous, err);
            jack_error ("ALSA: could not complete playback of %d frames: error = %d", contiguous, err);
            if (err != EPIPE && err != ESTRPIPE)
                return -1;
        }

        nframes -= contiguous;
        nwritten += contiguous;
    }
    return 0;
}

void
JackAlsaDriver::alsa_driver_delete (alsa_driver_t *driver)
{
    JSList *node;

    if (driver->midi)
        (driver->midi->destroy)(driver->midi);

    for (node = driver->clock_sync_listeners; node;
        node = jack_slist_next (node)) {
        free (node->data);
    }
    jack_slist_free (driver->clock_sync_listeners);
    
    if (driver->ctl_handle) {
		snd_ctl_close (driver->ctl_handle);
		driver->ctl_handle = 0;
	} 

    if (driver->ctl_handle) {
        snd_ctl_close (driver->ctl_handle);
        driver->ctl_handle = 0;
    } 

    if (driver->capture_handle) {
        snd_pcm_close (driver->capture_handle);
        driver->capture_handle = 0;
    }

    if (driver->playback_handle) {
        snd_pcm_close (driver->playback_handle);
        driver->capture_handle = 0;
    }

    if (driver->capture_hw_params) {
        snd_pcm_hw_params_free (driver->capture_hw_params);
        driver->capture_hw_params = 0;
    }

    if (driver->playback_hw_params) {
        snd_pcm_hw_params_free (driver->playback_hw_params);
        driver->playback_hw_params = 0;
    }

    if (driver->capture_sw_params) {
        snd_pcm_sw_params_free (driver->capture_sw_params);
        driver->capture_sw_params = 0;
    }

    if (driver->playback_sw_params) {
        snd_pcm_sw_params_free (driver->playback_sw_params);
        driver->playback_sw_params = 0;
    }

    if (driver->pfd) {
        free (driver->pfd);
    }

    if (driver->hw) {
        driver->hw->release (driver->hw);
        driver->hw = 0;
    }
    free(driver->alsa_name_playback);
    free(driver->alsa_name_capture);
    free(driver->alsa_driver);

    alsa_driver_release_channel_dependent_memory (driver);
    // steph
    //jack_driver_nt_finish ((jack_driver_nt_t *) driver);
    free (driver);
}

jack_driver_t *
JackAlsaDriver::alsa_driver_new (const char *name, char *playback_alsa_device,
                                 char *capture_alsa_device,
                                 jack_client_t *client,
                                 jack_nframes_t frames_per_cycle,
                                 jack_nframes_t user_nperiods,
                                 jack_nframes_t rate,
                                 int hw_monitoring,
                                 int hw_metering,
                                 int capturing,
                                 int playing,
                                 DitherAlgorithm dither,
                                 int soft_mode,
                                 int monitor,
                                 int user_capture_nchnls,
                                 int user_playback_nchnls,
                                 int shorts_first,
                                 jack_nframes_t capture_latency,
                                 jack_nframes_t playback_latency,
                                 alsa_midi_t *midi)
{
    int err;

    alsa_driver_t *driver;

    /*
    printf ("creating alsa driver ... %s|%s|%" PRIu32 "|%" PRIu32
    	"|%" PRIu32"|%" PRIu32"|%" PRIu32 "|%s|%s|%s|%s\n",
    	playing ? playback_alsa_device : "-",
    	capturing ? capture_alsa_device : "-", 
    	frames_per_cycle, user_nperiods, rate,
    	user_capture_nchnls,user_playback_nchnls,
    	hw_monitoring ? "hwmon": "nomon",
    	hw_metering ? "hwmeter":"swmeter",
    	soft_mode ? "soft-mode":"-",
    	shorts_first ? "16bit":"32bit");
    	*/

    driver = (alsa_driver_t *) calloc (1, sizeof (alsa_driver_t));

    jack_driver_nt_init ((jack_driver_nt_t *) driver);

    driver->midi = midi;
    driver->xrun_recovery = 0;

    //driver->nt_attach = (JackDriverNTAttachFunction) alsa_driver_attach;
    //driver->nt_detach = (JackDriverNTDetachFunction) alsa_driver_detach;
    //driver->read = (JackDriverReadFunction) alsa_driver_read;
    //driver->write = (JackDriverReadFunction) alsa_driver_write;
    //driver->null_cycle = (JackDriverNullCycleFunction) alsa_driver_null_cycle;
    //driver->nt_bufsize = (JackDriverNTBufSizeFunction) alsa_driver_bufsize;
    //driver->nt_start = (JackDriverNTStartFunction) alsa_driver_start;
    //driver->nt_stop = (JackDriverNTStopFunction) alsa_driver_stop;
    //driver->nt_run_cycle = (JackDriverNTRunCycleFunction) alsa_driver_run_cycle;

    driver->playback_handle = NULL;
    driver->capture_handle = NULL;
    driver->ctl_handle = 0;
    driver->hw = 0;
    driver->capture_and_playback_not_synced = FALSE;
    driver->max_nchannels = 0;
    driver->user_nchannels = 0;
    driver->playback_nchannels = user_playback_nchnls;
    driver->capture_nchannels = user_capture_nchnls;
    driver->playback_sample_bytes = (shorts_first ? 2 : 4);
    driver->capture_sample_bytes = (shorts_first ? 2 : 4);
    driver->capture_frame_latency = capture_latency;
    driver->playback_frame_latency = playback_latency;

    driver->playback_addr = 0;
    driver->capture_addr = 0;
    driver->playback_interleave_skip = NULL; 
    driver->capture_interleave_skip = NULL; 

    driver->silent = 0;
    driver->all_monitor_in = FALSE;
    driver->with_monitor_ports = monitor;

    driver->clock_mode = ClockMaster; /* XXX is it? */
    driver->input_monitor_mask = 0;   /* XXX is it? */

    driver->capture_ports = 0;
    driver->playback_ports = 0;
    driver->monitor_ports = 0;

    driver->pfd = 0;
    driver->playback_nfds = 0;
    driver->capture_nfds = 0;

    driver->dither = dither;
    driver->soft_mode = soft_mode;

    pthread_mutex_init (&driver->clock_sync_lock, 0);
    driver->clock_sync_listeners = 0;

    driver->poll_late = 0;
    driver->xrun_count = 0;
    driver->process_count = 0;

    driver->alsa_name_playback = strdup (playback_alsa_device);
    driver->alsa_name_capture = strdup (capture_alsa_device);

    if (alsa_driver_check_card_type (driver)) {
        alsa_driver_delete (driver);
        return NULL;
    }

    alsa_driver_hw_specific (driver, hw_monitoring, hw_metering);

    if (playing) {
        if (snd_pcm_open (&driver->playback_handle,
                          playback_alsa_device,
                          SND_PCM_STREAM_PLAYBACK,
                          SND_PCM_NONBLOCK) < 0) {
            switch (errno) {
                case EBUSY:
                    jack_error ("the playback device \"%s\" is "
                                "already in use. Please stop the"
                                " application using it and "
                                "run JACK again",
                                playback_alsa_device);
                    alsa_driver_delete (driver);
                    return NULL;
                    break;

                case EPERM:
                    jack_error ("you do not have permission to open "
                                "the audio device \"%s\" for playback",
                                playback_alsa_device);
                    alsa_driver_delete (driver);
                    return NULL;
                    break;
            }

            driver->playback_handle = NULL;
        }

        if (driver->playback_handle) {
            snd_pcm_nonblock (driver->playback_handle, 0);
        }
    }

    if (capturing) {
        if (snd_pcm_open (&driver->capture_handle,
                          capture_alsa_device,
                          SND_PCM_STREAM_CAPTURE,
                          SND_PCM_NONBLOCK) < 0) {
            switch (errno) {
                case EBUSY:
                    jack_error ("the capture device \"%s\" is "
                                "already in use. Please stop the"
                                " application using it and "
                                "run JACK again",
                                capture_alsa_device);
                    alsa_driver_delete (driver);
                    return NULL;
                    break;

                case EPERM:
                    jack_error ("you do not have permission to open "
                                "the audio device \"%s\" for capture",
                                capture_alsa_device);
                    alsa_driver_delete (driver);
                    return NULL;
                    break;
            }

            driver->capture_handle = NULL;
        }

        if (driver->capture_handle) {
            snd_pcm_nonblock (driver->capture_handle, 0);
        }
    }

    if (driver->playback_handle == NULL) {
        if (playing) {

            /* they asked for playback, but we can't do it */

            jack_error ("ALSA: Cannot open PCM device %s for "
                        "playback. Falling back to capture-only"
                        " mode", name);

            if (driver->capture_handle == NULL) {
                /* can't do anything */
                alsa_driver_delete (driver);
                return NULL;
            }

            playing = FALSE;
        }
    }

    if (driver->capture_handle == NULL) {
        if (capturing) {

            /* they asked for capture, but we can't do it */

            jack_error ("ALSA: Cannot open PCM device %s for "
                        "capture. Falling back to playback-only"
                        " mode", name);

            if (driver->playback_handle == NULL) {
                /* can't do anything */
                alsa_driver_delete (driver);
                return NULL;
            }

            capturing = FALSE;
        }
    }

    driver->playback_hw_params = 0;
    driver->capture_hw_params = 0;
    driver->playback_sw_params = 0;
    driver->capture_sw_params = 0;

    if (driver->playback_handle) {
        if ((err = snd_pcm_hw_params_malloc (
                       &driver->playback_hw_params)) < 0) {
            jack_error ("ALSA: could not allocate playback hw"
                        " params structure");
            alsa_driver_delete (driver);
            return NULL;
        }

        if ((err = snd_pcm_sw_params_malloc (
                       &driver->playback_sw_params)) < 0) {
            jack_error ("ALSA: could not allocate playback sw"
                        " params structure");
            alsa_driver_delete (driver);
            return NULL;
        }
    }

    if (driver->capture_handle) {
        if ((err = snd_pcm_hw_params_malloc (
                       &driver->capture_hw_params)) < 0) {
            jack_error ("ALSA: could not allocate capture hw"
                        " params structure");
            alsa_driver_delete (driver);
            return NULL;
        }

        if ((err = snd_pcm_sw_params_malloc (
                       &driver->capture_sw_params)) < 0) {
            jack_error ("ALSA: could not allocate capture sw"
                        " params structure");
            alsa_driver_delete (driver);
            return NULL;
        }
    }

    if (alsa_driver_set_parameters (driver, frames_per_cycle,
                                    user_nperiods, rate)) {
        alsa_driver_delete (driver);
        return NULL;
    }

    driver->capture_and_playback_not_synced = FALSE;

    if (driver->capture_handle && driver->playback_handle) {
        if (snd_pcm_link (driver->capture_handle,
                          driver->playback_handle) != 0) {
            driver->capture_and_playback_not_synced = TRUE;
        }
    }

    driver->client = client;
    return (jack_driver_t *) driver;
}

int JackAlsaDriver::Attach()
{
    JackPort* port;
    int port_index;
    unsigned long port_flags;
    char name[JACK_CLIENT_NAME_SIZE + JACK_PORT_NAME_SIZE];
    char alias[JACK_CLIENT_NAME_SIZE + JACK_PORT_NAME_SIZE];

    assert(fCaptureChannels < DRIVER_PORT_NUM);
    assert(fPlaybackChannels < DRIVER_PORT_NUM);

    port_flags = JackPortIsOutput | JackPortIsPhysical | JackPortIsTerminal;

    alsa_driver_t* alsa_driver = (alsa_driver_t*)fDriver;

    if (alsa_driver->has_hw_monitoring)
        port_flags |= JackPortCanMonitor;

    // ALSA driver may have changed the values
    JackAudioDriver::SetBufferSize(alsa_driver->frames_per_cycle);
    JackAudioDriver::SetSampleRate(alsa_driver->frame_rate);

    jack_log("JackAudioDriver::Attach fBufferSize %ld fSampleRate %ld", fEngineControl->fBufferSize, fEngineControl->fSampleRate);

    for (int i = 0; i < fCaptureChannels; i++) {
        snprintf(alias, sizeof(alias) - 1, "%s:capture_%u", fAliasName, i + 1);
        snprintf(name, sizeof(name) - 1, "%s:capture_%d", fClientControl.fName, i + 1);
        if ((port_index = fGraphManager->AllocatePort(fClientControl.fRefNum, name, JACK_DEFAULT_AUDIO_TYPE, (JackPortFlags)port_flags, fEngineControl->fBufferSize)) == NO_PORT) {
            jack_error("driver: cannot register port for %s", name);
            return -1;
        }
        port = fGraphManager->GetPort(port_index);
        port->SetAlias(alias);
        port->SetLatency(alsa_driver->frames_per_cycle + alsa_driver->capture_frame_latency);
        fCapturePortList[i] = port_index;
        jack_log("JackAudioDriver::Attach fCapturePortList[i] %ld ", port_index);
    }

    port_flags = JackPortIsInput | JackPortIsPhysical | JackPortIsTerminal;

    for (int i = 0; i < fPlaybackChannels; i++) {
        snprintf(alias, sizeof(alias) - 1, "%s:playback_%u", fAliasName, i + 1);
        snprintf(name, sizeof(name) - 1, "%s:playback_%d", fClientControl.fName, i + 1);
        if ((port_index = fGraphManager->AllocatePort(fClientControl.fRefNum, name, JACK_DEFAULT_AUDIO_TYPE, (JackPortFlags)port_flags, fEngineControl->fBufferSize)) == NO_PORT) {
            jack_error("driver: cannot register port for %s", name);
            return -1;
        }
        port = fGraphManager->GetPort(port_index);
        port->SetAlias(alias);
        // Add one buffer more latency if "async" mode is used...
        port->SetLatency((alsa_driver->frames_per_cycle * (alsa_driver->user_nperiods - 1)) +
                         ((fEngineControl->fSyncMode) ? 0 : fEngineControl->fBufferSize) + alsa_driver->playback_frame_latency);
        fPlaybackPortList[i] = port_index;
        jack_log("JackAudioDriver::Attach fPlaybackPortList[i] %ld ", port_index);

        // Monitor ports
        if (fWithMonitorPorts) {
            jack_log("Create monitor port ");
            snprintf(name, sizeof(name) - 1, "%s:monitor_%d", fClientControl.fName, i + 1);
            if ((port_index = fGraphManager->AllocatePort(fClientControl.fRefNum, name, JACK_DEFAULT_AUDIO_TYPE, JackPortIsOutput, fEngineControl->fBufferSize)) == NO_PORT) {
                jack_error ("ALSA: cannot register monitor port for %s", name);
            } else {
                port = fGraphManager->GetPort(port_index);
                port->SetLatency(alsa_driver->frames_per_cycle);
                fMonitorPortList[i] = port_index;
            }
        }
    }

    if (alsa_driver->midi) {
        int err = (alsa_driver->midi->attach)(alsa_driver->midi);
        if (err)
            jack_error ("ALSA: cannot attach MIDI: %d", err);
    }

    return 0;
}

int JackAlsaDriver::Detach()
{
    alsa_driver_t* alsa_driver = (alsa_driver_t*)fDriver;
    if (alsa_driver->midi)
        (alsa_driver->midi->detach)(alsa_driver->midi);

    return JackAudioDriver::Detach();
}

int JackAlsaDriver::Open(jack_nframes_t nframes,
                         jack_nframes_t user_nperiods,
                         jack_nframes_t samplerate,
                         bool hw_monitoring,
                         bool hw_metering,
                         bool capturing,
                         bool playing,
                         DitherAlgorithm dither,
                         bool soft_mode,
                         bool monitor,
                         int inchannels,
                         int outchannels,
                         bool shorts_first,
                         const char* capture_driver_name,
                         const char* playback_driver_name,
                         jack_nframes_t capture_latency,
                         jack_nframes_t playback_latency,
                         const char* midi_driver_name)
{
    // Generic JackAudioDriver Open
    if (JackAudioDriver::Open(nframes, samplerate, capturing, playing,
                              inchannels, outchannels, monitor, capture_driver_name, playback_driver_name,
                              capture_latency, playback_latency) != 0) {
        return -1;
    }

    alsa_midi_t *midi = 0;
    if (strcmp(midi_driver_name, "seq") == 0)
        midi = alsa_seqmidi_new((jack_client_t*)this, 0);
    else if (strcmp(midi_driver_name, "raw") == 0)
        midi = alsa_rawmidi_new((jack_client_t*)this);

    fDriver = alsa_driver_new ("alsa_pcm", (char*)playback_driver_name, (char*)capture_driver_name,
                               NULL,
                               nframes,
                               user_nperiods,
                               samplerate,
                               hw_monitoring,
                               hw_metering,
                               capturing,
                               playing,
                               dither,
                               soft_mode,
                               monitor,
                               inchannels,
                               outchannels,
                               shorts_first,
                               capture_latency,
                               playback_latency,
                               midi);
    if (fDriver) {
        // ALSA driver may have changed the in/out values
        fCaptureChannels = ((alsa_driver_t *)fDriver)->capture_nchannels;
        fPlaybackChannels = ((alsa_driver_t *)fDriver)->playback_nchannels;
        return 0;
    } else {
        JackAudioDriver::Close();
        return -1;
    }
}

int JackAlsaDriver::Close()
{
    JackAudioDriver::Close();
    alsa_driver_delete((alsa_driver_t*)fDriver);
    return 0;
}

int JackAlsaDriver::Start()
{
    return alsa_driver_start((alsa_driver_t *)fDriver);
}

int JackAlsaDriver::Stop()
{
    return alsa_driver_stop((alsa_driver_t *)fDriver);
}

int JackAlsaDriver::Read()
{
    /* Taken from alsa_driver_run_cycle */
    int wait_status;
    jack_nframes_t nframes;
    fDelayedUsecs = 0.f;

    nframes = alsa_driver_wait((alsa_driver_t *)fDriver, -1, &wait_status, &fDelayedUsecs);
 
    if (wait_status < 0)
        return -1;		/* driver failed */

    if (nframes == 0) {
        /* we detected an xrun and restarted: notify
         * clients about the delay. 
         */
        jack_log("ALSA XRun");
        NotifyXRun(fBeginDateUst, fDelayedUsecs);
        return -1;
    }

    if (nframes != fEngineControl->fBufferSize)
        jack_log("JackAlsaDriver::Read error nframes = %ld", nframes);
        
    // Has to be done before read
    JackDriver::CycleIncTime();

    return alsa_driver_read((alsa_driver_t *)fDriver, fEngineControl->fBufferSize);
}

int JackAlsaDriver::Write()
{
    return alsa_driver_write((alsa_driver_t *)fDriver, fEngineControl->fBufferSize);
}

void
JackAlsaDriver::jack_driver_init (jack_driver_t *driver)
{
    memset (driver, 0, sizeof (*driver));

    driver->attach = 0;
    driver->detach = 0;
    driver->write = 0;
    driver->read = 0;
    driver->null_cycle = 0;
    driver->bufsize = 0;
    driver->start = 0;
    driver->stop = 0;
}

void
JackAlsaDriver::jack_driver_nt_init (jack_driver_nt_t * driver)
{
    memset (driver, 0, sizeof (*driver));

    jack_driver_init ((jack_driver_t *) driver);

    driver->attach = 0;
    driver->detach = 0;
    driver->bufsize = 0;
    driver->stop = 0;
    driver->start = 0;

    driver->nt_bufsize = 0;
    driver->nt_start = 0;
    driver->nt_stop = 0;
    driver->nt_attach = 0;
    driver->nt_detach = 0;
    driver->nt_run_cycle = 0;
}

int JackAlsaDriver::is_realtime() const
{
    return fEngineControl->fRealTime;
}

int JackAlsaDriver::create_thread(pthread_t *thread, int priority, int realtime, void *(*start_routine)(void*), void *arg)
{
    return JackPosixThread::StartImp(thread, priority, realtime, start_routine, arg);
}

jack_port_id_t JackAlsaDriver::port_register(const char *port_name, const char *port_type, unsigned long flags, unsigned long buffer_size)
{
    jack_port_id_t port_index;
    int res = fEngine->PortRegister(fClientControl.fRefNum, port_name, port_type, flags, buffer_size, &port_index);
    return (res == 0) ? port_index : 0;
}

int JackAlsaDriver::port_unregister(jack_port_id_t port_index)
{
    return fEngine->PortUnRegister(fClientControl.fRefNum, port_index);
}

void* JackAlsaDriver::port_get_buffer(int port, jack_nframes_t nframes)
{
    return fGraphManager->GetBuffer(port, nframes);
}

int  JackAlsaDriver::port_set_alias(int port, const char* name)
{
    return fGraphManager->GetPort(port)->SetAlias(name);
}

jack_nframes_t JackAlsaDriver::get_sample_rate() const
{
    return fEngineControl->fSampleRate;
}

jack_nframes_t JackAlsaDriver::frame_time() const
{
    JackTimer timer;
    fEngineControl->ReadFrameTime(&timer);
    return timer.Time2Frames(GetMicroSeconds(), fEngineControl->fBufferSize);
}

jack_nframes_t JackAlsaDriver::last_frame_time() const
{
    JackTimer timer;
    fEngineControl->ReadFrameTime(&timer);
    return timer.CurFrame();
}

} // end of namespace


#ifdef __cplusplus
extern "C"
{
#endif

static
void
fill_device(
    jack_driver_param_constraint_desc_t ** constraint_ptr_ptr,
    uint32_t * array_size_ptr,
    const char * device_id,
    const char * device_description)
{
    jack_driver_param_value_enum_t * possible_value_ptr;

    //jack_info("%6s - %s", device_id, device_description);

    if (*constraint_ptr_ptr == NULL)
    {
        *constraint_ptr_ptr = (jack_driver_param_constraint_desc_t *)calloc(1, sizeof(jack_driver_param_value_enum_t));
        *array_size_ptr = 0;
    }

    if ((*constraint_ptr_ptr)->constraint.enumeration.count == *array_size_ptr)
    {
        *array_size_ptr += 10;
        (*constraint_ptr_ptr)->constraint.enumeration.possible_values_array =
            (jack_driver_param_value_enum_t *)realloc(
                (*constraint_ptr_ptr)->constraint.enumeration.possible_values_array,
                sizeof(jack_driver_param_value_enum_t) * *array_size_ptr);
    }

    possible_value_ptr = (*constraint_ptr_ptr)->constraint.enumeration.possible_values_array + (*constraint_ptr_ptr)->constraint.enumeration.count;
    (*constraint_ptr_ptr)->constraint.enumeration.count++;
    strcpy(possible_value_ptr->value.str, device_id);
    strcpy(possible_value_ptr->short_desc, device_description);
}

static
jack_driver_param_constraint_desc_t *
enum_alsa_devices()
{
    snd_ctl_t * handle;
    snd_ctl_card_info_t * info;
    snd_pcm_info_t * pcminfo_capture;
    snd_pcm_info_t * pcminfo_playback;
    int card_no = -1;
    char card_id[JACK_DRIVER_PARAM_STRING_MAX + 1];
    char device_id[JACK_DRIVER_PARAM_STRING_MAX + 1];
    char description[64];
    int device_no;
    bool has_capture;
    bool has_playback;
    jack_driver_param_constraint_desc_t * constraint_ptr;
    uint32_t array_size = 0;

    snd_ctl_card_info_alloca(&info);
    snd_pcm_info_alloca(&pcminfo_capture);
    snd_pcm_info_alloca(&pcminfo_playback);

    constraint_ptr = NULL;

    while(snd_card_next(&card_no) >= 0 && card_no >= 0)
    {
        sprintf(card_id, "hw:%d", card_no);

        if (snd_ctl_open(&handle, card_id, 0) >= 0 &&
            snd_ctl_card_info(handle, info) >= 0)
        {
            fill_device(&constraint_ptr, &array_size, card_id, snd_ctl_card_info_get_name(info));

            device_no = -1;

            while (snd_ctl_pcm_next_device(handle, &device_no) >= 0 && device_no != -1)
            {
                sprintf(device_id, "%s,%d", card_id, device_no);

                snd_pcm_info_set_device(pcminfo_capture, device_no);
                snd_pcm_info_set_subdevice(pcminfo_capture, 0);
                snd_pcm_info_set_stream(pcminfo_capture, SND_PCM_STREAM_CAPTURE);
                has_capture = snd_ctl_pcm_info(handle, pcminfo_capture) >= 0;

                snd_pcm_info_set_device(pcminfo_playback, device_no);
                snd_pcm_info_set_subdevice(pcminfo_playback, 0);
                snd_pcm_info_set_stream(pcminfo_playback, SND_PCM_STREAM_PLAYBACK);
                has_playback = snd_ctl_pcm_info(handle, pcminfo_playback) >= 0;

                if (has_capture && has_playback)
                {
                    snprintf(description, sizeof(description),"%s (duplex)", snd_pcm_info_get_name(pcminfo_capture));
                }
                else if (has_capture)
                {
                    snprintf(description, sizeof(description),"%s (capture)", snd_pcm_info_get_name(pcminfo_capture));
                }
                else if (has_playback)
                {
                    snprintf(description, sizeof(description),"%s (playback)", snd_pcm_info_get_name(pcminfo_playback));
                }
                else
                {
                    continue;
                }

                fill_device(&constraint_ptr, &array_size, device_id, description);
            }

            snd_ctl_close(handle);
        }
    }

    return constraint_ptr;
}

static
jack_driver_param_constraint_desc_t *
get_midi_driver_constraint()
{
    jack_driver_param_constraint_desc_t * constraint_ptr;
    jack_driver_param_value_enum_t * possible_value_ptr;

    //jack_info("%6s - %s", device_id, device_description);

    constraint_ptr = (jack_driver_param_constraint_desc_t *)calloc(1, sizeof(jack_driver_param_value_enum_t));
    constraint_ptr->flags = JACK_CONSTRAINT_FLAG_STRICT | JACK_CONSTRAINT_FLAG_FAKE_VALUE;

    constraint_ptr->constraint.enumeration.possible_values_array = (jack_driver_param_value_enum_t *)malloc(3 * sizeof(jack_driver_param_value_enum_t));
    constraint_ptr->constraint.enumeration.count = 3;

    possible_value_ptr = constraint_ptr->constraint.enumeration.possible_values_array;

    strcpy(possible_value_ptr->value.str, "none");
    strcpy(possible_value_ptr->short_desc, "no MIDI driver");

    possible_value_ptr++;

    strcpy(possible_value_ptr->value.str, "seq");
    strcpy(possible_value_ptr->short_desc, "ALSA Sequencer driver");

    possible_value_ptr++;

    strcpy(possible_value_ptr->value.str, "raw");
    strcpy(possible_value_ptr->short_desc, "ALSA RawMIDI driver");

    return constraint_ptr;
}

static
jack_driver_param_constraint_desc_t *
get_dither_constraint()
{
    jack_driver_param_constraint_desc_t * constraint_ptr;
    jack_driver_param_value_enum_t * possible_value_ptr;

    //jack_info("%6s - %s", device_id, device_description);

    constraint_ptr = (jack_driver_param_constraint_desc_t *)calloc(1, sizeof(jack_driver_param_value_enum_t));
    constraint_ptr->flags = JACK_CONSTRAINT_FLAG_STRICT | JACK_CONSTRAINT_FLAG_FAKE_VALUE;

    constraint_ptr->constraint.enumeration.possible_values_array = (jack_driver_param_value_enum_t *)malloc(4 * sizeof(jack_driver_param_value_enum_t));
    constraint_ptr->constraint.enumeration.count = 4;

    possible_value_ptr = constraint_ptr->constraint.enumeration.possible_values_array;

    possible_value_ptr->value.c = 'n';
    strcpy(possible_value_ptr->short_desc, "none");

    possible_value_ptr++;

    possible_value_ptr->value.c = 'r';
    strcpy(possible_value_ptr->short_desc, "rectangular");

    possible_value_ptr++;

    possible_value_ptr->value.c = 's';
    strcpy(possible_value_ptr->short_desc, "shaped");

    possible_value_ptr++;

    possible_value_ptr->value.c = 't';
    strcpy(possible_value_ptr->short_desc, "triangular");

    return constraint_ptr;
}

    static int
    dither_opt (char c, DitherAlgorithm* dither) 
    {
        switch (c) {
            case '-':
            case 'n':
                *dither = None;
                break;

            case 'r':
                *dither = Rectangular;
                break;

            case 's':
                *dither = Shaped;
                break;

            case 't':
                *dither = Triangular;
                break;

            default:
                fprintf (stderr, "ALSA driver: illegal dithering mode %c\n", c);
                return -1;
        }
        return 0;
    }

    SERVER_EXPORT const jack_driver_desc_t* driver_get_descriptor () 
    {
        jack_driver_desc_t * desc;
        jack_driver_param_desc_t * params;
        unsigned int i;

        desc = (jack_driver_desc_t*)calloc (1, sizeof (jack_driver_desc_t));
        
        strcpy(desc->name, "alsa");                                    // size MUST be less then JACK_DRIVER_NAME_MAX + 1
        strcpy(desc->desc, "Linux ALSA API based audio backend");      // size MUST be less then JACK_DRIVER_PARAM_DESC + 1
        
        desc->nparams = 18;
        params = (jack_driver_param_desc_t*)calloc (desc->nparams, sizeof (jack_driver_param_desc_t));

        i = 0;
        strcpy (params[i].name, "capture");
        params[i].character = 'C';
        params[i].type = JackDriverParamString;
        strcpy (params[i].value.str, "none");
        strcpy (params[i].short_desc,
                "Provide capture ports.  Optionally set device");
        strcpy (params[i].long_desc, params[i].short_desc);

        i++;
        strcpy (params[i].name, "playback");
        params[i].character = 'P';
        params[i].type = JackDriverParamString;
        strcpy (params[i].value.str, "none");
        strcpy (params[i].short_desc,
                "Provide playback ports.  Optionally set device");
        strcpy (params[i].long_desc, params[i].short_desc);

        i++;
        strcpy (params[i].name, "device");
        params[i].character = 'd';
        params[i].type = JackDriverParamString;
        strcpy (params[i].value.str, "hw:0");
        strcpy (params[i].short_desc, "ALSA device name");
        strcpy (params[i].long_desc, params[i].short_desc);
        params[i].constraint = enum_alsa_devices();

        i++;
        strcpy (params[i].name, "rate");
        params[i].character = 'r';
        params[i].type = JackDriverParamUInt;
        params[i].value.ui = 48000U;
        strcpy (params[i].short_desc, "Sample rate");
        strcpy (params[i].long_desc, params[i].short_desc);

        i++;
        strcpy (params[i].name, "period");
        params[i].character = 'p';
        params[i].type = JackDriverParamUInt;
        params[i].value.ui = 1024U;
        strcpy (params[i].short_desc, "Frames per period");
        strcpy (params[i].long_desc, params[i].short_desc);

        i++;
        strcpy (params[i].name, "nperiods");
        params[i].character = 'n';
        params[i].type = JackDriverParamUInt;
        params[i].value.ui = 2U;
        strcpy (params[i].short_desc, "Number of periods of playback latency");
        strcpy (params[i].long_desc, params[i].short_desc);

        i++;
        strcpy (params[i].name, "hwmon");
        params[i].character = 'H';
        params[i].type = JackDriverParamBool;
        params[i].value.i = 0;
        strcpy (params[i].short_desc, "Hardware monitoring, if available");
        strcpy (params[i].long_desc, params[i].short_desc);

        i++;
        strcpy (params[i].name, "hwmeter");
        params[i].character = 'M';
        params[i].type = JackDriverParamBool;
        params[i].value.i = 0;
        strcpy (params[i].short_desc, "Hardware metering, if available");
        strcpy (params[i].long_desc, params[i].short_desc);

        i++;
        strcpy (params[i].name, "duplex");
        params[i].character = 'D';
        params[i].type = JackDriverParamBool;
        params[i].value.i = 1;
        strcpy (params[i].short_desc,
                "Provide both capture and playback ports");
        strcpy (params[i].long_desc, params[i].short_desc);

        i++;
        strcpy (params[i].name, "softmode");
        params[i].character = 's';
        params[i].type = JackDriverParamBool;
        params[i].value.i = 0;
        strcpy (params[i].short_desc, "Soft-mode, no xrun handling");
        strcpy (params[i].long_desc, params[i].short_desc);

        i++;
        strcpy (params[i].name, "monitor");
        params[i].character = 'm';
        params[i].type = JackDriverParamBool;
        params[i].value.i = 0;
        strcpy (params[i].short_desc, "Provide monitor ports for the output");
        strcpy (params[i].long_desc, params[i].short_desc);

        i++;
        strcpy (params[i].name, "dither");
        params[i].character = 'z';
        params[i].type = JackDriverParamChar;
        params[i].value.c = 'n';
        strcpy (params[i].short_desc, "Dithering mode");
        strcpy (params[i].long_desc,
                "Dithering mode:\n"
                "  n - none\n"
                "  r - rectangular\n"
                "  s - shaped\n"
                "  t - triangular");
        params[i].constraint = get_dither_constraint();

        i++;
        strcpy (params[i].name, "inchannels");
        params[i].character = 'i';
        params[i].type = JackDriverParamUInt;
        params[i].value.i = 0;
        strcpy (params[i].short_desc,
                "Number of capture channels (defaults to hardware max)");
        strcpy (params[i].long_desc, params[i].short_desc);

        i++;
        strcpy (params[i].name, "outchannels");
        params[i].character = 'o';
        params[i].type = JackDriverParamUInt;
        params[i].value.i = 0;
        strcpy (params[i].short_desc,
                "Number of playback channels (defaults to hardware max)");
        strcpy (params[i].long_desc, params[i].short_desc);

        i++;
        strcpy (params[i].name, "shorts");
        params[i].character = 'S';
        params[i].type = JackDriverParamBool;
        params[i].value.i = FALSE;
        strcpy (params[i].short_desc, "Try 16-bit samples before 32-bit");
        strcpy (params[i].long_desc, params[i].short_desc);

        i++;
        strcpy (params[i].name, "input-latency");
        params[i].character = 'I';
        params[i].type = JackDriverParamUInt;
        params[i].value.i = 0;
        strcpy (params[i].short_desc, "Extra input latency (frames)");
        strcpy (params[i].long_desc, params[i].short_desc);

        i++;
        strcpy (params[i].name, "output-latency");
        params[i].character = 'O';
        params[i].type = JackDriverParamUInt;
        params[i].value.i = 0;
        strcpy (params[i].short_desc, "Extra output latency (frames)");
        strcpy (params[i].long_desc, params[i].short_desc);

        i++;
        strcpy (params[i].name, "midi-driver");
        params[i].character = 'X';
        params[i].type = JackDriverParamString;
        strcpy (params[i].value.str, "none");
        strcpy (params[i].short_desc, "ALSA MIDI driver name (seq|raw)");
        strcpy (params[i].long_desc,
                "ALSA MIDI driver:\n"
                " none - no MIDI driver\n"
                " seq - ALSA Sequencer driver\n"
                " raw - ALSA RawMIDI driver\n");
        params[i].constraint = get_midi_driver_constraint();

        desc->params = params;
        return desc;
    }

    SERVER_EXPORT Jack::JackDriverClientInterface* driver_initialize(Jack::JackLockedEngine* engine, Jack::JackSynchro* table, const JSList* params) 
    {
        jack_nframes_t srate = 48000;
        jack_nframes_t frames_per_interrupt = 1024;
        unsigned long user_nperiods = 2;
        const char *playback_pcm_name = "hw:0";
        const char *capture_pcm_name = "hw:0";
        int hw_monitoring = FALSE;
        int hw_metering = FALSE;
        int capture = FALSE;
        int playback = FALSE;
        int soft_mode = FALSE;
        int monitor = FALSE;
        DitherAlgorithm dither = None;
        int user_capture_nchnls = 0;
        int user_playback_nchnls = 0;
        int shorts_first = FALSE;
        jack_nframes_t systemic_input_latency = 0;
        jack_nframes_t systemic_output_latency = 0;
        const JSList * node;
        const jack_driver_param_t * param;
        const char *midi_driver = "none";

        for (node = params; node; node = jack_slist_next (node)) {
            param = (const jack_driver_param_t *) node->data;

            switch (param->character) {

                case 'C':
                    capture = TRUE;
                    if (strcmp (param->value.str, "none") != 0) {
                        capture_pcm_name = strdup (param->value.str);
                        jack_log("capture device %s", capture_pcm_name);
                    }
                    break;

                case 'P':
                    playback = TRUE;
                    if (strcmp (param->value.str, "none") != 0) {
                        playback_pcm_name = strdup (param->value.str);
                        jack_log("playback device %s", playback_pcm_name);
                    }
                    break;

                case 'D':
                    playback = TRUE;
                    capture = TRUE;
                    break;

                case 'd':
                    playback_pcm_name = strdup (param->value.str);
                    capture_pcm_name = strdup (param->value.str);
                    jack_log("playback device %s", playback_pcm_name);
                    jack_log("capture device %s", capture_pcm_name);
                    break;

                case 'H':
                    hw_monitoring = param->value.i;
                    break;

                case 'm':
                    monitor = param->value.i;
                    break;

                case 'M':
                    hw_metering = param->value.i;
                    break;

                case 'r':
                    srate = param->value.ui;
                    jack_log("apparent rate = %d", srate);
                    break;

                case 'p':
                    frames_per_interrupt = param->value.ui;
                    jack_log("frames per period = %d", frames_per_interrupt);
                    break;

                case 'n':
                    user_nperiods = param->value.ui;
                    if (user_nperiods < 2)	/* enforce minimum value */
                        user_nperiods = 2;
                    break;

                case 's':
                    soft_mode = param->value.i;
                    break;

                case 'z':
                    if (dither_opt (param->value.c, &dither)) {
                        return NULL;
                    }
                    break;

                case 'i':
                    user_capture_nchnls = param->value.ui;
                    break;

                case 'o':
                    user_playback_nchnls = param->value.ui;
                    break;

                case 'S':
                    shorts_first = param->value.i;
                    break;

                case 'I':
                    systemic_input_latency = param->value.ui;
                    break;

                case 'O':
                    systemic_output_latency = param->value.ui;
                    break;

                case 'X':
                    midi_driver = strdup(param->value.str);
                    break;
            }
        }

        /* duplex is the default */
        if (!capture && !playback) {
            capture = TRUE;
            playback = TRUE;
        }

        Jack::JackAlsaDriver* alsa_driver = new Jack::JackAlsaDriver("system", "alsa_pcm", engine, table);
        Jack::JackDriverClientInterface* threaded_driver = new Jack::JackThreadedDriver(alsa_driver);
        // Special open for ALSA driver...
        if (alsa_driver->Open(frames_per_interrupt, user_nperiods, srate, hw_monitoring, hw_metering, capture, playback, dither, soft_mode, monitor,
                              user_capture_nchnls, user_playback_nchnls, shorts_first, capture_pcm_name, playback_pcm_name,
                              systemic_input_latency, systemic_output_latency, midi_driver) == 0) {
            return threaded_driver;
        } else {
            delete threaded_driver; // Delete the decorated driver
            return NULL;
        }
    }

#ifdef __cplusplus
}
#endif