[alsa-devel] HDMI LPCM (7.1) with AMD/FGLRX

Takashi Iwai tiwai at suse.de
Mon Aug 8 09:16:58 CEST 2011

At Sun, 7 Aug 2011 21:17:46 +0200,
Andrée 'Glaucous' wrote:
> Hello.
> I'm wondering if there's any ongoing development on multichannel sound
> support for HDMI - LPCM/5.1/7.1, not bitstreamed audio such as DTS/AC3
> (which works).
> I've tried both a AMD HD 4870 and AMD HD 6870, on both 2 channel and
> bitstreamed audio works with ALSA, but not LPCM. LPCM works perfectly (5.1,
> 7.1) on Windows.
> According to the mailing list there seem to have been some activity in this
> area (January or so), but no success. I'd gladly try out patches.

Check whether your HDMI codec chip is processed via
patch_generic_hdmi() in patch_hdmi.c.  Some ATI codecs are via
patch_atihdmi() and it doesn't support multi-channel LPCM.

If it's through patch_generic_hdmi(), basically it should work as is,
since the very same function is used by Intel and Nvidia HDMI, too, and
LPCM works on them.  Of course, some unknown ATI-specific things might
be missing.  But first check whether ELD validity is set, i.e. whether
the video driver passes the right ELD to HDMI auido side.


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