From mboxrd@z Thu Jan  1 00:00:00 1970
From: James Cloos <cloos@jhcloos.com>
Subject: Re: [PATCH v5] drm/i915: pass ELD to HDMI/DP audio
	driver
Date: Sun, 04 Sep 2011 06:57:23 -0400
Message-ID: <m3r53wa82c.fsf@jhcloos.com>
References: <20110902081428.GA19621@localhost>
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In-Reply-To: <20110903211510.GA11600@localhost> (Wu Fengguang's message of
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To: Wu Fengguang <fengguang.wu@intel.com>
Cc: Keith Packard <keithp@keithp.com>, "Wang,
	Zhenyu Z" <zhenyu.z.wang@intel.com>, "intel-gfx@lists.freedesktop..." <intel-gfx@lists.freedesktop.org>, "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>, "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>, Ben Skeggs <bskeggs@redhat.com>, Jeremy Bush <contractfrombelow@gmail.com>, Christopher White <c.white@pulseforce.com>, "Fu,
	Michael" <michael.fu@intel.com>, "Bossart,
	Pierre-louis" <pierre-louis.bossart@intel.com>
List-Id: alsa-devel@alsa-project.org

>>>>> "WF" == Wu Fengguang <fengguang.wu@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.

-JimC
-- 
James Cloos <cloos@jhcloos.com>         OpenPGP: 1024D/ED7DAEA6