Disable ATI HDMI audio from snd_hda_intel (was Re: Disable PCI devices via systemd)

[Raman Gupta]

On 07/31/2013 03:40 AM, poma wrote:
> https://www.kernel.org/doc/Documentation/sound/alsa/ALSA-Configuration.txt
> - Common parameters for top sound card modules

This actually doesn't provide any information on the "enable"
parameter for snd-hda-intel, weirdly enough.

> modinfo snd_hda_intel | grep enable:
> parm:           enable:Enable Intel HD audio interface. (array of bool)

Ah, I missed *array of* bool there! I was assuming this was a single
enable/disable. Nice.

> e.g.
> /etc/modprobe.d/snd-hda-intel.conf
> options snd-hda-intel enable=1,0,0

Thanks Poma, that example was perfect!

For future posterity, since I couldn't find this documented anywhere
else, the enable parameter is an array of booleans that can
enable/disable each card driven by the snd-hda-intel module. Look for
"HDA-Intel" in "cat /proc/asound/cards" e.g.:

 0 [U0x46d0x8c9    ]: USB-Audio - [...]
                      [...]
 1 [PCH            ]: HDA-Intel - [...]
                      [...]
 2 [HDMI           ]: HDA-Intel - [...]
                      [...]
 3 [HDMI_1         ]: HDA-Intel - [...]
                      [...]

The three cards listed that are driven by "HDA-Intel" are PCH, HDMI,
and HDMI_1 so to disable both HDMI cards, the enable parameter is "1,0,0".

I think this is a cleaner solution than disabling the PCI devices.

Regards,
Raman