[alsa-devel] [PATCH v5] drm/i915: pass ELD to HDMI/DP audio driver

James Cloos cloos at jhcloos.com
Sun Sep 4 12:57:23 CEST 2011

>>>>> "WF" == Wu Fengguang <fengguang.wu at intel.com> writes:

WF> ... If only the stereo playback capability is reported, the user
WF> won't be able to start 8-channel playback; if the 8-channel ELD is
WF> reported, then user space applications may send 8-channel samples
WF> down, however the user may actually be listening to the 2-channel
WF> monitor and not connecting speakers to the 8-channel monitor.

WF>  Overall, it's more safe to report maximum profiles to the user
WF> space, so that the user can at least be able to do 8-channel
WF> playback if he want to.

Be aware that many TVs will either refuse the display anything or pop-up
an OSD warning whenever they receive hdmi audio which they cannot handle.

Sending 8-channel in your example may render the stereo-only monitor useless.

That said, one step at a time is reasonable.  But eventually you will 
require configurability and/or per-monitor audio control even when the
video is cloned.

James Cloos <cloos at jhcloos.com>         OpenPGP: 1024D/ED7DAEA6

More information about the Alsa-devel mailing list