[alsa-devel] Audio Driver Works In Ubuntu but Crash in Debian After 2nd Run

[Raymond Yau]

>
> I discovered one thing which lead me to believe something is wrong in my
> *.pointer* callback. I would like to share it for expert suggestions.
>
> So when a audio playback starts I initialize the buffer pointer to "0" in
> the *.prepare* function. During my 1st playback the audio driver works
> great, I see the *.pointer* function getting called a lot of times.
>
> I update the buffer pointer  in the URB completion function. Here goes a
> code segment from my URB completion function:
>
> https://gist.github.com/azizulhakim/d24a36ef753f9a1536fa
>
>
>
> And this is my *.pointer* function:
>
> https://gist.github.com/azizulhakim/b15b002f74e77f88cd5a
>
>
> Now during the 2nd playback, the driver initializes the buffer pointer to
> "0" again inside the *.prepare* function. And then I see it calls the
> *.pointer* function only once and afterwards stop with the error message
*ALSA
> sound/core/pcm_lib.c:1910 playback write error (DMA or IRQ trouble?)*
>
>
> So I stopped initializing the buffer pointer to "0" during the second
> playback assuming that the buffer pointer should stay at the place it
> stopped from previous playback. But that also didn't work for me. I get
the
> same error message. Note that same driver works on Ubuntu without any
> problem and as many times as I want.
>
>
> It would be really helpful if I get some suggestion from the given code.
In
> case you wonder, the full code is available here
> <https://github.com/azizulhakim/beagleusb/blob/master/beagle-audio.c

Do your driver really support one period per buffer when you specify
.periods_min  = 1 ?