Comments on: Disabling NVIDIA’s HDMI Audio Under Linux

By: Rob Williams

Rob Williams — Fri, 03 May 2013 04:39:00 +0000

If it can work for a slacker, it can work for anyone! Glad it worked ;-)

By: slacker

slacker — Fri, 03 May 2013 04:34:00 +0000

Thanks much! The blacklist method worked flawlessly for me with newly installed Slackware 14.

By: Rob Williams

Rob Williams — Wed, 17 Apr 2013 01:51:00 +0000

I am glad you got things working! Thanks a ton for the information. Sorry for your hassles… I know how it is.

By: DrLex

DrLex — Mon, 15 Apr 2013 15:43:00 +0000

All right, I fixed it. The trick is that when giving module parameters to snd-hda-intel, it is possible to give comma-separated lists to pass the arguments to the different cards. Otherwise, when giving only a single argument, it will always be applied to the first card. Passing an argument to the second card only can be done by starting the argument with a comma.
Because I cannot be sure that the HDMI card will always be at position 0, I simply spam the magical fix parameter to both cards like this in /etc/modprobe.d/alsa-base.conf:

options snd-hda-intel position_fix=3,3

At first I thought it was possible to select a certain card (the one I needed is “SB”) by using e.g. “snd-hda-intel id=SB position_fix=3”, but what this will do is renaming the first card to “SB”, which is of course enormously confusing.

By: DrLex

DrLex — Mon, 15 Apr 2013 10:43:00 +0000

Nice try, but no cigar. The snd_hda_codec_hdmi module is gone alright, but the device is still there, only without controls.
I found out that it is possible to disable specific cards by supplying the probe_mask parameter to modprobe, but there is no way to disable the HDMI device without disabling the Realtek, it seems they are fused together. There should be a way to prevent the GPU from presenting its HDMI audio device at all. Theoretically, using the kernel parameter radeon.audio=0 should work, but it does not.
In the meantime I have verified that we did not have the distorted audio with an older kernel in Debian Squeeze. We may revert to that one, or simply plug in an USB sound card.

By: Rob Williams

Rob Williams — Sat, 13 Apr 2013 18:16:00 +0000

Enjoy your weekend. If you need some help next week just hit-me-up.

By: DrLex

DrLex — Sat, 13 Apr 2013 17:14:00 +0000

That looks promising, I’ll look into it when I get back to work. Thanks! But first, a relaxing weekend without fighting snd-hda-intel.

By: Rob Williams

Rob Williams — Fri, 12 Apr 2013 19:17:00 +0000

Alright, so I’m not sure when this change happened, but in recent kernels, the Intel HDA driver has gone module, as this screenshot shows. Here, you could disable the HDMI/DisplayPort portion while leaving everything else intact (like the Realtek). If you’re able to upgrade your kernel to a recent version and recompile, that should solve your problem.

By: Rob Williams

Rob Williams — Fri, 12 Apr 2013 19:04:00 +0000

That’s beyond frustrating. I’m at a loss at the moment as to how to bypass this, unless there’s ANOTHER switch that specifically disables the HDMI portion of the driver. It’s easy to suggest just going the add-in route as well to ignore the GPU entirely, but so many audio cards simply use the snd-hda-intel driver. My main audio card is an ASUS Xonar, so I’m fortunate enough to be able to avoid that hassle.

If I think of anything I’ll post here again.

By: DrLex

DrLex — Fri, 12 Apr 2013 14:44:00 +0000

Guess what: I have an ATI-based board with a built-in Realtek ALC892 sound card that needs snd-hda-intel to work. But the first sound card is always set to the built-in HDMI. I can fix this through asound.conf, no problem. But there is another typical Linux sound problem.

Typical for these Realtek things is that some voodoo parameters need to be passed to the kernel module to fix clicking sounds while recording. Adding something like “options snd-hda-intel position_fix=2″ to modprobe.d/alsa-base.conf should work. But it does nothing, because it seems that all options are applied to the first snd-hda-intel based card, which is of course the useless HDMI.

I have been fighting for hours to either get that HDMI thing obliterated, or to force the ALC892 to get ID 0 instead of 1. It seems hopeless. The intro to your article is perfectly accurate: configuring sound in Linux is a nightmare.