I running the latest nvidia driver (180.51) on an Apple TV which has a nVidia G72M [Quadro NVS 110M/GeForce Go 7300] GPU. The Apple TV uses a Silicon Image SiI 1930 to drive the HDMI output.
The SiI 1930 is connected to a Realtek ALC885 codec chip using the HD-Audio interface. It shows up as an ALSA audio device. By default the SiI 1930 embeds audio packets in the HDMI data stream. When I use the open-source nv driver I am able to play audio via HDMI using aplay. I hear the audio from my TV:
aplay -Dplughw:0,3 /usr/share/sounds/question.wav
As soon as I start the nVidia driver, the driver disables the HDMI audio data. aplay still reports the wav file is playing, but there are no audio packets in the HDMI data stream and no audio comes out of my TV.
It appears the nVidia driver started disabling the HMDI audio after version 100.14.19. HDMI audio works with version 100.14.19 of the nVidia driver.
Many people have the opposite problem. The newer nVidia drivers enable HDMI audio by default. I assume they are using other GPUs (8000 series, 9000 series). On the GeForce Go 7300 GPU, HDMI audio appears to now be disabled by default.
I would like a way to re-enable HDMI audio. I have posted more information on this thread: