poll blocked after prepare state

[Harald Schuster <schuster@technikum-wien.at>]

We found out that in some cases after the underrun the  
snd_pcm_dshare_start function is called and in some cases  
snd_pcm_dshare_start and the snd_pcm_hw_start function is called. When  
both functions are called the codec stops playback.

Zitat von Takashi Iwai <tiwai@suse.de>:

> On Mon, 25 Jun 2018 15:43:15 +0200,
> Harald Schuster wrote:
>>
>> Hi
>> The codec is the TI tlv320aic3x and the buffersize is set to 64 and
>> the periodsize is set to 32 in the asound.conf. We use the pjProject
>> for the audioprocessing and the internal period time is 4ms and the
>> sample rate is 8000 Hz. The second codec is a USB codec which has no
>> problems. Our scenario is that a incoming VOIP call is connected to
>> the both codec (I2s and USB) and the USB codec starts the playback
>> without any problems and the tlv320 sometimes works but when a
>> underrun accours it crash!
>
> Is it really so hardware-specific problem?
>
> And, did you follow the recent development / fixes if it's about
> dshare plugin?  There have been lots of changes.
>
> I'm not asking about updating the kernels.  The question is rather
> about alsa-lib.
>
>
> Takashi
>
>>
>> best regards Harald
>>
>>
>> Zitat von Takashi Iwai <tiwai@suse.de>:
>>
>> > On Mon, 25 Jun 2018 11:59:02 +0200,
>> > Harald Schuster wrote:
>> >>
>> >>
>> >> Hi
>> >> We are not able to update our system. We are using USB codecs which
>> >> are working fine but they are using the snd_pcm_hw_prepare function.
>> >> The Problem only exists for the I2S codec in our system. When i
>> >> changed the buffer size in the asound.conf for the codec the problem
>> >> allready exists but it arise not so often because there is not so
>> >> often a underrun. Is there any hint where i could lock for the
>> >> problem?!
>> >
>> > Well, with that little information, it's hard to advice anything...
>> >
>> >
>> > Takashi
>> >
>> >> br Harald
>> >>
>> >> Zitat von Takashi Iwai <tiwai@suse.de>:
>> >>
>> >> > On Fri, 22 Jun 2018 20:36:12 +0200,
>> >> > Harald Schuster wrote:
>> >> >>
>> >> >>
>> >> >> Zitat von Takashi Iwai <tiwai@suse.de>:
>> >> >>
>> >> >> > On Fri, 22 Jun 2018 15:29:21 +0200,
>> >> >> > Harald Schuster wrote:
>> >> >> >>
>> >> >> >> I found out that an underrun occours and so the  
>> pcm_prepare function
>> >> >> >> for pcm_direct is called and then pcm_start_dshare is called. Both
>> >> >> >> functions returns without any error but the playback path  
>> is blocked
>> >> >> >> in the snd_pcm_wait_nocheck function. I read that there  
>> was an similar
>> >> >> >> problem before in the group but i didn't found any  
>> solution. Is this a
>> >> >> >> problem in the driver and how can i go forward to fix it.  
>> The codec is
>> >> >> >> a tlv320aic3x-audio. Thanks for your help.
>> >> >> >
>> >> >> > Does this happen with the very latest alsa-lib git version?
>> >> >> > Just to be sure.
>> >> >> >
>> >> >> >
>> >> >> > Takashi
>> >> >> > _______________________________________________
>> >> >> > Alsa-devel mailing list
>> >> >> > Alsa-devel@alsa-project.org
>> >> >> > http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>> >> >>
>> >> >> Hi
>> >> >> We are using k4.1.15-6QP+ga2066af.
>> >> >
>> >> > I'm asking the alsa-lib, not kernel.
>> >> >
>> >> > And 4.1.x is very old...  Please check either 4.17.x or latest Linus
>> >> > tree whether the problem persists, too.
>> >> >
>> >> >
>> >> > Takashi
>> >> > _______________________________________________
>> >> > Alsa-devel mailing list
>> >> > Alsa-devel@alsa-project.org
>> >> > http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>> >>
>> >>
>> >>
>> >> _______________________________________________
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>> >>
>> > _______________________________________________
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>>
>>
>>
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