[alsa-devel] ALSA lib pcm_hw.c:1466:(_snd_pcm_hw_open) Unknown field chmap

[Takashi Iwai]

At Thu, 03 Oct 2013 21:15:51 +0200,
Alexander Stein wrote:
> 
> Hi,
> 
> I get this error message from several games I got recently. There is either not sound at all or it is choppy. This was with alsa-lib-1.0.27.1. So I downgraded to 1.0.26 and everything was fine. I compiled alsa-lib-1.0.27.1 myself and started them using LD_LIBRARY_PATH: everything worked. So I assumed there is something in the config files which has changed. Comparing them I noticed some changes in /usr/share/alsa/cards/Audigy2.conf. Those lines were added:
> chmap [ "UNKNOWN" "FL,FR" ]
> chmap [ "UNKNOWN" "RL,RR" ]
> chmap [ "UNKNOWN" "FC,LFE" ]
> chmap [ "UNKNOWN" "SL,SR" ]
> 
> See alsa-lib commits 5ba11d69dafbd4502469fd957b4580169779664c and ec7acfc408856cfe71a122e3b5387463d7b3d919. Updating to 1.0.27.1 again and commenting those lines out everything is ok now.
> 
> So I'm wondering what is the reason for this error message? How to fix that?

The problem is that the old alsa-lib without chmap support is
referring to the new config files.  Downgrade the files in
/usr/share/alsa/cards accordingly.  The lack of chmap definitions
isn't too serious.


Takashi