[alsa-devel] [PATCH] ASoC: davinci-mcasp: Correct rx format unit configuration

[Peter Ujfalusi]

On 01/14/2015 01:11 PM, Pascal Huerst wrote:
> Hey Peter, all,
> 
> the patch (8e3006d02b46a722729a3bbd6a774eae99c6c8b8), causes lots of
> terrible noise on a custom built am33xx based board, if I map the input
> to the output like so:
> 
> arecord -f S16_LE -r 48000 -c2 -D hw:0,1 -F 0 --period-size=102
> 4 -B 0 --buffer-size=4096 | aplay -D hw:0,0 -

FWIW the -F0 and -B0 is redundant and you can use -fdat instead of -f S16_LE
-r 48000 -c2

> If I undo your changes, everything works fine. Tested with 3.14.23 and
> 3.18.1.

You mean only this single commit?

> Do you have any Idea, what might cause that behavior?

No, I don't. I quickly checked on am335x, am437x and on J6 boards and the
command you are using works w/o any issue or distortion in recorded audio.

what codec or codecs are you using? I see that you record from hw:0,1 and play
it back to hw:0,0
Can you check if the recorded sample alone is correct? Just record it to a
file and look at it on the PC. I did the same and the recorded sample looks
fine on my PC as well.

Looking at the patch again, I still think it is a valid fix.

-- 
Péter