Anssi Hannula anssi.hannula@iki.fi writes:
This is a known issue, the NVIDIA MCP79/7A HDMI hardware has incorrect channel mapping.
I reported this several months ago as "Wrong channel order with multichannel HDMI on MCP7A": http://www.spinics.net/lists/alsa-devel/msg35948.html (there are some earlier reports from 2009 as well)
Great, thanks for confirming it's not just me.
I'm using this workaround at the moment: pcm.!hdmi { type route slave.pcm "cards.HDA-Intel.pcm.hdmi.0:CARD=NVidia,AES0=0x4,AES1=0x82,AES2=0x0,AES3=0x2" ttable.0.0 1 ttable.1.1 1 ttable.2.4 1 ttable.3.5 1 ttable.4.2 1 ttable.5.3 1 ttable.6.6 1 ttable.7.7 1 }
I can confirm that this fixes things for me.
(not a perfect workaround as I'm hardcoding AESx instead of using the ones provided as arguments, but at least you get the idea)
I don't understand this comment, but hopefully if I just put the above in my asound.conf, all should be fine, right?
As for the preferred solution to this problem, as far as I understand, that would be for the driver to have some ioctl that would provide alsa-lib information about the unusual channel mapping, and alsa-lib could then remap the channels using a channel remapping plugin.
Alternatively, can the fix just be hardcoded for this audio card?
Dan