The commit
53d7d69d8ffdfa60c5b66cc2e9ee0774aaaef5c0
ALSA: hdmi - support infoframe for DisplayPort
dropped the initialization of CA field accidentally.
This resulted in only two-channel LPCM mode on Nvidia machines.
Reference: kernel bug 28592
https://bugzilla.kernel.org/show_bug.cgi?id=28592
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Cc: <stable@kernel.org>