[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:
> 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
> 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,
Open Source Technology Center, Intel ltd.
$gpg --keyserver wwwkeys.pgp.net --recv-keys 4D781827
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