[Intel-gfx] [PATCH 1/2] drm/i915: Check VBIOS value for determining LVDS dual channel mode, too

[Keith Packard]

<#part sign=pgpmime>
On Tue, 20 Mar 2012 13:04:41 +0100, Takashi Iwai <tiwai at suse.de> wrote:

> Since checking the lid state is tricky and unreliable, the practical
> check would be simply reading the first LVDS reg and seeing whether it
> was initialized or not.  It seems that it reads to 0x02 when booted
> with the lid close, which is LVDS_DETECTED bit.

Right, lid-detect is not useful, so I suggested using the new code path
only if the LVDS was *not* actually running at startup time. That should
avoid almost all common cases that work correctly today.

-- 
keith.packard at intel.com