[alsa-devel] dmix produces garbled sound on ARM

[Ihar Filipau]

On 6/9/16, Takashi Iwai <tiwai at suse.de> wrote:
> On Thu, 09 Jun 2016 16:05:42 +0200,
> Ihar Filipau wrote:
>>
>> The only thing so far I have found is `aplay --dump-hw-params`, but it
>> seem to display the allowed ranges, not the defaults/the params which
>> are used.
>
> You just need to check what "aplay -v ..." shows.  For example,
> % aplay -Dplug:dmix -v foo.wav

[ Replying back to the list, since exchange of the lengthy outputs is
over for now. ]

My parameters are nearly identical to yours (except for the
differences which could be attributed to my 32-bit vs your 64-bit
systems, and the hardware S16_LE vs S32_LE). Yet the problem persists.

I have checked the Raspberry Pi forums/mail list and it seems that
"dmix" works fine there. Thus, the problem might be related to the hw
driver.

How can I localize the problem? Is there any way to intercept the data
stream which goes to the sound card, and compare the content between
normal direct playback vs dmix?

P.S. Though the window is closing for my investigations. I'm starting
to prepare a workaround: applications shouldn't keep pcm open all the
time, should open pcm when needed, and they should retry with a delay
if opening pcm failed.