AC97 problems with pxa...

[Eric Miao]

On Wed, Apr 7, 2010 at 5:50 AM, Jakob Viketoft
<jakob.viketoft at bitsim.com> wrote:
>
> Hello!
>
> I'm trying to add sound support to a Toradex Colibri 270 v2 card, but
> have run into some strangeness which I don't quite understand. The v2 of
> this card uses the WM9712 codec and I've written a machine driver to tie
> the codec and the pxa2xx-ac97 driver together. I'm using the 2.6.33.1
> kernel and my machine driver is a simplified version of the tosa driver
> (no power management or headphone jack logic). However, I get two problems:
> 1. Internal clock and headphone output is turned off in the
> AC97_POWERDOWN register and I can't see where to (properly) turn it on,
> neither in kernel space or in userland. No-one else using this codec
> seem to be doing it.
> 2. The init function defined in my snd_soc_card struct doesn't seem to
> get called, resulting in way too many mixer settings (I have a number of
> snd_soc_dapm_nc_pin calls) with alsa, but might it also have something
> to do with problem 1?
>
> When explicitly writing 0 (the ugly way) to the AC97_POWERDOWN register
> I get perfect sound output, but I would like to do it the right way.
>
> Two error reports from the dmesg output that might be relevant:
> * pxa2xx_ac97_try_cold_reset: cold reset timeout (GSR=0x44)
> * Error: Driver 'pxa2xx-ac97' is already registered, aborting...
>
> The AC97 interface is added in the machine initialization through the
> pxa_set_ac97_info() in the same way as tosa and many others and this
> could explain the second error message...
>
> Any insight would be appreciated!
>

Better if you could come up with a patch or source code for analysis.