Hello.
Takashi Iwai wrote:
I committed your patch now on HG tree, as it's likely OK from the
possible breakage on other apps, too.
OK, first I have to apologize for
not providing a test-case - its still
in my todo if you need it. There are
still a few things unclear, like, for
example, how it fixes the portaudio,
if, as you say, such an apps are not
touching the code in question.
Anyway... as I said already, there are
few more problems that were hidden
before and are not any more. (I really
tried to warn you :)
For example, mpg123 will now consume
100% of CPU because of the nasty loop
in snd_pcm_write_areas()...
I am using something like the attached
patch, but maybe you can come up with
the better solution.
Quick summary: mpg123 sets avail_min=1,
so the loop spins without any rest.
Before, the value was "adjusted", so
it didn't spin that nasty way.
Anyway, I swear that I'll never read any mails during my next
vacation. That was so exhausting to be dragged to a lengthy
discussion for band-aiding a badly designed compoment... :)
But now, unfortunately, you won't get
away from that. :)
The hack used to cover more problems...
--- pcm.c.old 2007-11-04 17:57:01.000000000 +0300
+++ pcm.c 2007-11-07 21:34:59.000000000 +0300
@@ -6465,19 +6465,35 @@
goto _end;
}
if ((state == SND_PCM_STATE_RUNNING &&
- (snd_pcm_uframes_t)avail < pcm->avail_min &&
size > (snd_pcm_uframes_t)avail) ||
(size >= pcm->xfer_align &&
(snd_pcm_uframes_t)avail < pcm->xfer_align)) {
+ snd_pcm_sframes_t avail_min, orig_avail_min;
+ snd_pcm_sw_params_t params;
if (pcm->mode & SND_PCM_NONBLOCK) {
err = -EAGAIN;
goto _end;
}
+ avail_min = (size < pcm->period_size ?
+ size : pcm->period_size);
+ orig_avail_min = pcm->avail_min;
+ if (avail_min != pcm->avail_min) {
+ snd_pcm_sw_params_current(pcm, ¶ms);
+ params.avail_min = avail_min;
+ snd_pcm_sw_params(pcm, ¶ms);
+ }
+
err = snd_pcm_wait(pcm, -1);
if (err < 0)
break;
+
+ if (orig_avail_min != pcm->avail_min) {
+ params.avail_min = orig_avail_min;
+ snd_pcm_sw_params(pcm, ¶ms);
+ }
+
goto _again;
}
if ((snd_pcm_uframes_t) avail > pcm->xfer_align)
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