[alsa-devel] Random inverted audio channels

[Alexandre BOUIN]

> > This embedded project includes a AT91SAM9260 CPU and a WM8900 codec.
> 
> JOOI, is this the WM8900 driver in our dev branch or another one?  It
> shouldn't make any difference either way what driver is used for the
> codec, though, so long as it is generating the relevant clock signals.

We are porting a WM8900 driver from a 8731 one. It fit quite well our
requirements and should not be the same as your dev branch.
Sincerely, It didn't know you're working on it.

> > We have an issue : when we play a right channel stereo track, sound
> is
> > played on right channel, but sometimes on left.
> > This issue could happen right after starting kernel, or later after
> 10-20
> > sounds played.
> > With Frank Mandarino, we've checked any issue from SSC(audio bus) or
> PDC
> > (dma) controlers, but no much success.
> 
> > Any idea to help us debugging this issue would be welcome !
> 
> The most likely issue here is a DMA underrun but from what you say you
> may already have ruled that out?  It would be helpful if you could run
> through the debugging you've already done here.

I had traced the addresses sent into PDC (soc/at91-pcm.c), and are always
the same.
What other traces are you looking for ?

> One thing to try if your design allows it would be to try making the
> CPU the master.  That should reduce the number of variables, at least.

You're right I should try this way, so it would confirm if I have or not an
issue with my LRC clock.