[alsa-devel] [PATCH 0/3] enable HDMI audio output for HDMI monitors V2

Wang, Zhenyu Z zhenyu.z.wang at intel.com
Thu Nov 13 03:05:46 CET 2008

On 2008.11.07 14:23:38 +0800, Wu Fengguang wrote:
> Hello,
> We can now enjoy music on HDMI monitors that are attached to Intel G35/G45
> chipsets with the following X.org intel driver patches
>       [PATCH 1/3] introduce i830_hdmi_priv.has_hdmi_sink
>       [PATCH 2/3] enable Intel G45 integrated HDMI audio output
>       [PATCH 3/3] enable Intel G35 SDVO HDMI audio output
> _and_ the corresponding ALSA patch posted at
> http://mailman.alsa-project.org/pipermail/alsa-devel/2008-November/012158.html
> The patches are tested OK on Intel DG45ID board, HP 2230s notebook and
> ASUS P5E-VM board.

Pushed xf86-video-intel patches. Thanks!

If you have HDMI output with intel graphics chips, you can test this now.

- alsa patch is within above mail, or get it from

- after loading snd_hda_intel, 'aplay -l' should give you a list of devices
  that contains Intel HDMI device. Use that device for PCM. Current supports

- build xf86-video-intel git master to enable HDMI audio within video driver.

> Since the HDMI audio requires both audio and video driver support to function
> well, I'd like to provide an overview here.
> 1) driver components:
> 	A) ALSA: audio driver (the above link)
> 	B) Xorg: audio output enabling (this patchset)
> 	C) Xorg: EDID/ELD information (patches to be submitted by Ma Ling)
> 2) summary of the feature sets:
> 	- basic 2-channel audio:
> 		(A) is required, (B) is mostly required, (C) is not needed
> 	- 2+ multichannel audio:
> 		not tested yet; in theory we need (C) to get HDMI monitor's
> 		speaker allocation configuration; there are also bandwidth
> 		constraints that should be coordinated between audio/video
> 		drivers in the future.
> 	- non-LPCM audio:
> 		not tested yet; need more work in ALSA code.
> 3) summary of the work flow:
> 	- basic audio output: (A) and (B)
> 		- ALSA HDMI driver: enable pin out and unmute
> 		- ALSA HDMI driver: fill audio infoframe and enable its transmission
> 		- Xorg intel driver: enable audio output
> 	- ELD info for advanced audio capabilities: (A) and (C)
> 		- Xorg xserver: get/parse/store EDID extensions
> 		- Xorg xserver: transform EDID into ELD
> 		- Xorg intel driver: feed ELD to hardware
> 		- Xorg intel driver: set ELD-Valid flag to inform audio driver of new ELD
> 		- ALSA HDMI driver: response to unsolicited response triggered by ELDV
> 		- ALSA HDMI driver: get ELD from hardware
> 		- ALSA HDMI driver: parse and show ELD info
> 		- ALSA HDMI driver: update hardware capabilities/constraints
> 				    according to ELD (TBD)
> That describes my understandings of HDMI audio, comments and discussions are
> warmly welcome.
> Thank you,
> Fengguang
> --

Open Source Technology Center, Intel ltd.

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