linux-kernel - Re: [PATCH] drm: ignore LVDS on intel graphics systems that lie about having it

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Date:	Mon, 6 Apr 2009 13:29:53 -0400
From:	Jarod Wilson <jarod@...hat.com>
To:	Jesse Barnes <jbarnes@...tuousgeek.org>
Cc:	dri-devel@...ts.sourceforge.net, xorg-devel@...ts.x.org,
	linux-kernel@...r.kernel.org, notting@...hat.com,
	Zhenyu Wang <zhenyu.z.wang@...el.com>,
	Fu Michael <michael_fu@...ux.intel.com>
Subject: Re: [PATCH] drm: ignore LVDS on intel graphics systems that lie about having it

On Monday 06 April 2009 12:52:16 Jesse Barnes wrote:
> On Mon, 6 Apr 2009 10:11:25 -0400
> Jarod Wilson <jarod@...hat.com> wrote:
> 
> > There are a number of small form factor desktop systems with Intel
> > mobile graphics chips that lie and say they have an LVDS. With kernel
> > mode-setting, this becomes a problem, and makes native resolution
> > boot go haywire -- for example, my Dell Studio Hybrid, hooked to a
> > 1920x1080 display claims to have a 1024x768 LVDS, and the resulting
> > graphical boot on the 1920x1080 display uses only the top left
> > 1024x768, and auto-configured X will end up only 1024x768 as well.
> > With this change, graphical boot and X both do 1920x1080 as expected.
> > 
> > Note that we're simply embracing and extending the early bail-out code
> > in place for the Mac Mini here. The xorg intel driver uses pci
> > subsystem device and vendor id for matching, while we're using dmi
> > lookups here. The MSI addition is courtesy of and tested by Bill
> > Nottingham.
> > 
> > One minor issue... Current Fedora rawhide, video playback using Xv
> > makes X go off into the weeds with this patch added, but that's a bug
> > elsewhere, still confident this patch DTRT.
> > 
> > Signed-off-by: Jarod Wilson <jarod@...hat.com>
> > Tested-by: Bill Nottingham <notting@...hat.com>
> 
> The 2D driver has a similar set of quirks, but since we started that
> list we've found that the VBIOS should contain a pretty reliable table
> indicating which outputs are available, including LVDS.  I think if we
> can figure out how to parse it reliably (accounting for VBIOS
> versioning and structure size changes) we shouldn't need this patch.
> If we can't get that done in time for 2.6.30 though I'm all for
> including this.

Sounds like a plan to me. Either way, would this patch still make sense
for submission to the 2.6.29.x stable series? I've already tacked it
onto the Fedora 2.6.29 kernel builds, fwiw.

-- 
Jarod Wilson
jarod@...hat.com
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