I've got a GT240 NVidia card and PCM HDMI audio is limited to two channels with kernel 2.6.37. Other NVidia cards are probably affected as well.
Reverting http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=53d7d69d8ffdfa60c5b66cc2e9ee0774aaaef5c0 make things going back to normal.
Fixed in sound git tree. The patch is attached below.
Created attachment 46852 [details]
Handled-By : Takashi Iwai <firstname.lastname@example.org>
Patch : https://bugzilla.kernel.org/attachment.cgi?id=46852
merged for .38-rc5:
Author: Takashi Iwai <email@example.com>
Date: Tue Feb 8 17:25:49 2011 +0100
ALSA: hda - Fix missing CA initialization for HDMI/DP
Any chance this issue was re-introduced? I'm running Ubuntu 13.10 and after latest updates I no longer get 5.1 sound only 2 channel. I've swapped hardware to confirm it is not the card. Changed drivers etc nothing seems to work.
How do go about confirm if this is the same issue or a new bug?