[alsa-devel] [RFC] [PATCH] ASoC: OMAP: full duplex mode fix

Arun KS arunks at mistralsolutions.com
Mon Aug 3 19:53:31 CEST 2009

On Mon, Aug 3, 2009 at 7:00 AM, Janusz Krzysztofik <jkrzyszt at tis.icnet.pl>wrote:

> Jarkko Nikula wrote:
>> On Mon, 3 Aug 2009 03:32:04 +0200
>> Janusz Krzysztofik <jkrzyszt at tis.icnet.pl> wrote:
>>  This patch tries to correct the problem of full duplex mode not working
>>> over a single McBSP based CPU DAI.
>>> Created against linux-2.6.31-rc5.
>>> Tested on Amstrad Delta.
>>>  Do you have some specific test case how to trigger this? I haven't
>> seen this on 2420 or 34xx (e.g. with 'arecord -d 1 -f dat |aplay') but
>> I have no doubt that this can happen on 1510. At least this doesn't
>> cause any harm on Beagle so I'm fine with the fix.
> Hi,
> I made more testing on my OMAP1510 and found out that I could get your
> example usage working without my patch, but only if started like this:
>        arecord -D hw:0,0 -f S16_LE|aplay -D hw:0,0
> If I start the same with "-D hw:0,0" omitted from aplay, it doesn't work
> any longer, waiting forever. It definitelly doesn't work if I start capture
> and playback one after another, no matter which one goes first (record while
> playing or play while recording). So it looks like starting both streams
> simultaneously can do the job, but a short delay breaks it.
> With my patch, it seems to work fine for me in all cases.
> Jarkko, have you ever tried it on your OMAP2/3 with parallel playback and
> capture started one after another, not simultaneously?
> Arun, can your snd-soc-osk9512 work on OMAP1610 in full duplex mode without
> any limitations?


Haven't done testing in full duplex mode.
I don't have access to osk5912 board now. If someone has got osk and do the
testing it ll be good. It  ll take at least another 2 more month for me to
do the testing on osk.


> If the problem appears to be OMAP1510 or AMS_DELTA specific, I can add a
> check for a machine or cpu type to avoid braking unaffected machines.
> Thanks,
> Janusz
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