View source for NVidia GT220 HDMI sound

== Summary ==
The nVidia GT220 (together with the other GT2xx cards) no longer has a S/PDIF input plug on it. Instead, it comes with a built-in sound card that isn't supported by ALSA yet.

== Status ==
<b>Experimental</b>

The people at XMBC have a page in that Wiki which points to a [http://wiki.xbmc.org/index.php?title=HOW-TO_set_up_HDMI_audio_on_nVidia_GeForce_G210,_GT220,_or_GT240 patch that makes sound work through the HDMI connector of the GT220 and GT240].

* PCM sound: works
* Passthrough for AC3 and DTS: does not work
* GT240s have some issues with PCM

The patch from the XBMC wiki creates four sound devices for some reason (3, 7, 8, 9), but only one of them plays any sound: device 7. You need to unmute it with alsamixer.

== Notes ==
Because the "hdmi" device is no longer valid with a GT220, I took the liberty of making the following changes, in order to maintain maximum software compatibility:

* File: /etc/modprobe.d/gt220.conf
 options snd-hda-intel enable_msi=0 index=1

* File: /etc/asound.conf
 pcm.!hdmi {
         type hw
         card 1
         device 7
 }
 
 ctl.!hdmi {
         type hw
         card 1
         device 7
 }

Notice that because of parameter "index=1" for snd-hda-intel, the card will always have index 1, even if you disable or remove your real sound card (either on-board or removing it from its PCI slot) so asound.conf doesn't need to track it.

Also notice that if your real sound card is driven by snd-hda-intel you may get unexpected results and you are expected to update this wiki page if you find a solution.