diff --git a/linux/alsa/alsa_driver.c b/linux/alsa/alsa_driver.c
index 6a7b92d6..055ac369 100644
--- a/linux/alsa/alsa_driver.c
+++ b/linux/alsa/alsa_driver.c
@@ -323,10 +323,22 @@ alsa_driver_setup_io_function_pointers (alsa_driver_t *driver)
 					sample_move_d32l24_sS;
 				break;
                     case SND_PCM_FORMAT_S32_LE:
-                        driver->write_via_copy = driver->quirk_bswap?
-                            sample_move_d32_sSs:
-                            sample_move_d32_sS;
+					{
+						int bits = snd_pcm_hw_params_get_sbits(driver->playback_hw_params);
+						if (bits == 32)
+						{
+							driver->write_via_copy = driver->quirk_bswap?
+								sample_move_d32_sSs:
+								sample_move_d32_sS;
+						}
+						else
+						{
+							driver->write_via_copy = driver->quirk_bswap?
+								sample_move_d32u24_sSs:
+								sample_move_d32u24_sS;
+						}
                         break;
+					}
                     default:
                         jack_error("unsupported 4 byte sample_format");
                         exit (1);
@@ -357,20 +369,32 @@ alsa_driver_setup_io_function_pointers (alsa_driver_t *driver)
 					sample_move_dS_s24;
 				break;
 			case 4:
-                switch (driver->capture_sample_format)
-                {
-                    case SND_PCM_FORMAT_S24_LE:
-                    case SND_PCM_FORMAT_S24_BE:
+				switch (driver->capture_sample_format)
+				{
+					case SND_PCM_FORMAT_S24_LE:
+					case SND_PCM_FORMAT_S24_BE:
 				driver->read_via_copy = driver->quirk_bswap?
 					sample_move_dS_s32l24s:
 					sample_move_dS_s32l24;
 				break;
-                    case SND_PCM_FORMAT_S32_LE:
-                        driver->read_via_copy = driver->quirk_bswap?
-                            sample_move_dS_s32s:
-                            sample_move_dS_s32;
-                        break;
-                    default:
+					case SND_PCM_FORMAT_S32_LE:
+					{
+						int bits = snd_pcm_hw_params_get_sbits(driver->capture_hw_params);
+						if (bits == 32)
+						{
+							driver->read_via_copy = driver->quirk_bswap?
+								sample_move_dS_s32s:
+								sample_move_dS_s32;
+						}
+						else
+						{
+							driver->read_via_copy = driver->quirk_bswap?
+								sample_move_dS_s32u24s:
+								sample_move_dS_s32u24;
+						}
+						break;
+					}
+					default:
                         jack_error("unsupported 4 byte sample_format");
                         exit (1);
                 }