From 08233661064df1adde4362bbdbc2cd5466577202 Mon Sep 17 00:00:00 2001 From: elboulangero Date: Sat, 13 Apr 2013 18:36:31 +0200 Subject: [PATCH] Fix xrun_recovery in ALSA clients. According to the ALSA documentation, snd_pcm_readi() returns -ESTRPIPE when a suspend event occured. But xrun_recovery() checks for -EAGAIN instead. If the ALSA client is connected to the ALSA loopback device, it leads to an infinite loop in the client when the computer is resumed from sleep. The client takes up to 99% of the CPU resources. The problem is fixed by a proper error checking of snd_pcm_readi(). A word of caution however: on kernels prior to 3.8, it will trigger a bug in the snd-aloop driver, and may lead to a kernel oops. The kernel fix can be found there: http://www.spinics.net/lists/stable-commits/msg23379.html Signed-off-by: elboulangero --- example-clients/alsa_in.c | 2 +- example-clients/alsa_out.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/example-clients/alsa_in.c b/example-clients/alsa_in.c index a32a3a53..c6af131c 100644 --- a/example-clients/alsa_in.c +++ b/example-clients/alsa_in.c @@ -111,7 +111,7 @@ static int xrun_recovery(snd_pcm_t *handle, int err) { if (err < 0) printf("Can't recover from underrun, prepare failed: %s\n", snd_strerror(err)); return 0; - } else if (err == -EAGAIN) { + } else if (err == -ESTRPIPE) { while ((err = snd_pcm_resume(handle)) == -EAGAIN) usleep(100); /* wait until the suspend flag is released */ if (err < 0) { diff --git a/example-clients/alsa_out.c b/example-clients/alsa_out.c index be25e403..47779d10 100644 --- a/example-clients/alsa_out.c +++ b/example-clients/alsa_out.c @@ -111,7 +111,7 @@ static int xrun_recovery(snd_pcm_t *handle, int err) { if (err < 0) printf("Can't recovery from underrun, prepare failed: %s\n", snd_strerror(err)); return 0; - } else if (err == -EAGAIN) { + } else if (err == -ESTRPIPE) { while ((err = snd_pcm_resume(handle)) == -EAGAIN) usleep(100); /* wait until the suspend flag is released */ if (err < 0) {