[alsa-devel] Bug in setting channels, related to recent ELD/EDID changes?

[Anssi Hannula]

On 23.12.2010 04:22, VDR User wrote:
> Hi.  After updating my stable kernel from 2.6.35.7 to 2.6.36.2, I get
> a problem when tuning HDTV channels that use surround sound.  The
> error I get is as follows:
> 
> audio_alsa_out: Cannot set number of channels to 6 (err=-22:Invalid argument)
> audio_out: open failed!
> 
> With the following xine error:
> ---------------------- (ERROR) ----------------------
> The audio device is unavailable. Please verify if another program
> already uses it.
> 
> ['Audio device unavailable' '']
> ------------------ (END OF ERROR) -------------------

What are the contents of /proc/asound/NVidia/eld* and
/proc/asound/NVidia/codec* ?

> This problem did not exist in 2.6.35.7 alsa drivers (using
> snd-hda-intel).  I have noticed that there has been recent changes
> associated with ELD/EDID that sets limitations on channels.  First of
> all I think this is a horrible idea since many devices don't even
> contain correct EDID.  It's simply too unreliable to use.

Well, I haven't yet seen any EDID which contained incorrect audio
information. Also, in case we find no information in the ELD, all
channels and formats are allowed.

> Secondly,
> could the above problem be related to those changes?

It could.

> If anyone knows a fix for this or can point me in the right direction
> (aside of going back to 2.6.35.7), PLEASE fill me in.
> 
> Here are some system specs:
> debian testing
> kernel snd-hda-intel driver used for hdmi audio on nvidia gt240 video card
> hdmi going to 7.1 surround sound receiver & setup
> 
> Any help is greatly appreciated!
> 
> Best regards,
> Derek


-- 
Anssi Hannula