[Alsa-devel] [patch] pcm-record (was cs46xx record (Thinkpad A22) => deadlock)

[Wilfried Weissmann]

I dug a little around in the code. The infinitive loop was caused by being stuck in DRAINING mode. snd_pcm_lib_read1() returns -EPIPE in this case (pcm_lib.c: 2146). Then we return to snd_pcm_oss_read3() which continues to call this function until jdoomsday (= SysRq+b). I changed the code to call snd_pcm_update_hw_ptr() before that. The patch is attached. It *seems* to fix it. You want to have a _real_ close look at that if you want to apply the patch, as it is just a shot in the dark. At least I know now that the problem is (I figured it out by inserting printk).

greetings,
Wilfried

--- pcm_lib.c.bak       Tue Oct 29 13:40:50 2002
+++ pcm_lib.c   Tue Oct 29 14:44:42 2002
@@ -2138,7 +2138,7 @@
                snd_pcm_uframes_t frames, appl_ptr, appl_ofs;
                snd_pcm_uframes_t avail;
                snd_pcm_uframes_t cont;
-               if (runtime->sleep_min == 0 && runtime->status->state == 
SNDRV_PCM_STATE_RUNNING)
+               if (runtime->sleep_min == 0 && ( runtime->status->state == 
+SNDRV_PCM_STATE_RUNNING || runtime->status->state == SNDRV_PCM_STATE_DRAINING))
                        snd_pcm_update_hw_ptr(substream);
                avail = snd_pcm_capture_avail(runtime);
                if (runtime->status->state == SNDRV_PCM_STATE_DRAINING) {