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.
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
--
_______________________________________________
xorg mailing list
[email protected]
http://lists.freedesktop.org/mailman/listinfo/xorg
