From: Chris Wilson <chris@chris-wilson.co.uk>
To: Keith Packard <keithp@keithp.com>,
Jesse Barnes <jbarnes@virtuousgeek.org>,
Dave Airlie <airlied@gmail.com>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915: no LVDS on Intel SandyBridge SDVs
Date: Wed, 22 Dec 2010 14:47:51 +0000 [thread overview]
Message-ID: <5b55a1$j1mgqr@fmsmga002.fm.intel.com> (raw)
In-Reply-To: <yunwrn2q405.fsf@aiko.keithp.com>
On Tue, 21 Dec 2010 12:12:42 -0800, Keith Packard <keithp@keithp.com> wrote:
> On Tue, 21 Dec 2010 19:55:15 +0000, Chris Wilson <chris@chris-wilson.co.uk> wrote:
>
> > The test we do is simply whether the LVDS i2c pins are addressable. That
> > requires differentiating between an IO error and a NAK, which at present
> > is only possible using GMBUS. The reference to this method I found in the
> > BIOS writers' guide, but of course that doesn't actually explain how it
> > works (especially the significance of address 0xa0).
>
> I can't see how that would work without an i2c receiver on the DDC
> bus...
>
> But, then, I've been surprised by DDC in the past, so perhaps it's worth
> a test on a device that has LVDS but does not have EDID.
It works as far back as I can test, a 915GM without a VBIOS or EDID.
I've had one person report that it can distinguish a phantom LVDS panel on
one g33 based all-in-one computer. Though not all hardware is equal, and
prudence suggests wider testing. ;-)
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
prev parent reply other threads:[~2010-12-22 14:48 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-20 20:05 [PATCH] drm/i915: no LVDS on Intel SandyBridge SDVs Jesse Barnes
2010-12-20 20:46 ` Chris Wilson
2010-12-21 2:43 ` Dave Airlie
2010-12-21 2:53 ` Jesse Barnes
2010-12-21 11:36 ` Chris Wilson
2010-12-21 18:14 ` Keith Packard
2010-12-21 19:55 ` Chris Wilson
2010-12-21 20:12 ` Keith Packard
2010-12-22 14:47 ` Chris Wilson [this message]
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