[alsa-devel] [PATCH 12/13] drm: bridge/dw_hdmi-ahb-audio: add audio driver

[Russell King - ARM Linux]

On Sat, May 09, 2015 at 07:49:44PM +0300, Anssi Hannula wrote:
> (Of course having userspace set them requires that the device has a
> proper entry in /usr/share/alsa/cards and the pcm device is accessed via
> the standard "hdmi" or "iec958" device names which perform the channel
> status word setup. I guess the ARM SoC stuff generally doesn't bother
> with that, explaining a bit why some kernel drivers set them by themselves).

I'm not sure that's sufficient - I haven't yet found where in the ALSA
userspace, the AES bits are appropriately set according to the sample
rate.

> HDMI_FC_AUDICONF2 register default value is 0x00, which means plain
> stereo (per CEA-861). If this is what goes on to the HDMI link as well,
> the audio sink should ignore the other channels.
> Did you check that multichannel PCM actually works? (maybe I'm just
> missing where CA is set)

I have no way to test multichannel support - not everyone has a plethora
of HDMI devices readily accessible.

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