On Tue, 20 Nov 2007, Takashi Iwai wrote:
changeset: 2352:39d34d6a4587 tag: tip user: tiwai date: Tue Nov 20 15:29:10 2007 +0100 files: src/pcm/pcm.c description: pcm - Limit the avail_min minimum size
Fix avail_min if it's less than period_size. The too small avail_min is simply useless and the cause of CPU hog with rate plugin.
diff -r b1d1733e52f8 -r 39d34d6a4587 src/pcm/pcm.c --- a/src/pcm/pcm.c Mon Nov 19 08:07:19 2007 +0100 +++ b/src/pcm/pcm.c Tue Nov 20 15:29:10 2007 +0100 @@ -5577,6 +5577,12 @@ int snd_pcm_sw_params_set_avail_min(snd_ #endif { assert(pcm && params);
- /* Fix avail_min if it's below period size. The period_size
* defines the minimal wake-up timing accuracy, so it doesn't* make sense to set below that.*/- if (val < pcm->period_size)
val = pcm->period_size;}
I think that this patch is wrong. We may use system timers to increase (fine-tune) "interrupt" latencies for pcm streams - see tick time in driver and library.
Jaroslav
----- Jaroslav Kysela perex@perex.cz Linux Kernel Sound Maintainer ALSA Project