Message-Id: <0d30dc$k822nk@orsmga001.jf.intel.com>
Date: Sun, 21 Nov 2010 10:30:43 +0000
To: Chris Vine <chris@cvine.freeserve.co.uk>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: kernel 2.6.37-rc2 breaks i915 graphics
In-Reply-To: <20101121102344.7c590b99@laptop.homenet>
References: <20101121102344.7c590b99@laptop.homenet>
From: Chris Wilson <chris@chris-wilson.co.uk>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1393
Lines: 28

On Sun, 21 Nov 2010 10:23:44 +0000, Chris Vine <chris@cvine.freeserve.co.uk> wrote:
> Hi,
> 
> With kernel 2.6.37-rc2, i915 graphics usually fails on boot-up after
> modesetting with my Lenovo S12 netbook which uses the Intel 945GME
> Express Integrated Graphics Controller.  It displays up to the point at
> which modesetting takes place and then usually goes blank.
> 
> There may be some kind of race at work here: first, sometimes (maybe 1
> times in 4) graphics comes up correctly on a first cold boot, but I
> have never managed to get it to come up on a warm reboot. Secondly,
> graphics can be restored when I know (but cannot see) that boot-up has
> concluded, simply by suspending the laptop and then resuming.  Resuming
> the laptop after a suspend always brings up the graphics correctly.

Add drm.debug=0xe to your boot commandline and compare if there is any
difference between a successful cold boot, a broken cold boot and a warm
boot. Similarly, comparing the output of intel_reg_dumper after each
should yield a few clues as to what stage in the boot process we fail.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre
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