Re: [alsa-devel] How to interrupt snd_pcm_writei in blocking mode?
Takashi Iwai <tiwai <at> suse.de> writes:
At Thu, 30 Jun 2005 20:42:28 +0200, Hynek Hanke wrote:
Hynek Hanke wrote:
I'm running it in two separate threads. One does all the
preparations and calls
snd_pcm_writei() in blocking mode. The other one then decides it
wants to stop
playing, so it calls snd_pcm_drop(). This causes the device to
switch from
state RUNNING to state SETUP, but the snd_pcm_writei() hangs
forever and never
returns. Why is this so?
Well, but pcm_lib.c::snd_pcm_lib_write1() should check the state SETUP and break the loop immediately. Ditto for snd_pcm_lib_read1(). The quick hack is below. Please give a shot.
I tried to apply the patch to the 2.6.11 kernel but after compilation/instalation, there is no difference. It still hangs.
Logfiles say
it was in the state RUNNING just before snd_pcm_drop() was called and
got into
state SETUP immediatelly after. The logfile from the other thread shows snd_pcm_writei() never returns (not even after the sound would surely be completed).
Hmm, then still something is missing. I'll check on it later.
So, what can I do? Do I really have to use the non-blocking mode or is this supposed to work (if I take care about all the other thread related issues myself)? My colleague is reporting it's working for him under some different configuration.
The non-blocking mode and poll() should work (hopefully :) If not, let me know.
Can I enable some debugging messages or something to help you to see what's wrong?
Check the code flow in snd_pcm_lib_write1(). You can see the places my patch tried to fix. Basically, the thread should be woken up and get out of the loop. But according to your report, it didn't work as expected by some reason...
Takashi
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Hello Takashi, We have the same problem. snd_pcm_writei blocks when we switch between playback and record continuously for several times.
Is this issue is fixed in any kernel versions. I am running kernel version 2.6.31 Alsa version 1.0.18
is it a issue of buffers we allocate using snd_pcm_hw_params_set_period_size_near
whats the way to calculate this value and how should be the ideal value.
I appreciate any help/suggestions in this regard.
Thanks and Regards, Giri
participants (1)
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Giridhara