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Date: Mon, 4 Mar 2013 18:49:43 +0100
Message-ID: <CAKMK7uGGN6ikKr4KvaJJ7iLPgK2KwE5RsgUn=WqTtvU-ryM5nQ@mail.gmail.com>
Subject: Re: i915 black screen introduced by ACPI changes
From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: Chris Li <lkml@chrisli.org>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>, linux-kernel@vger.kernel.org,
        robert.moore@intel.com, feng.tang@intel.com, len.brown@intel.com,
        Linus Torvalds <torvalds@linux-foundation.org>
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On Mon, Mar 4, 2013 at 6:11 PM, Chris Li <lkml@chrisli.org> wrote:
> To recap, the black screen first show up after the ACPI change to use widows 8
> string. The i915_setmode function did not crash. The printk output
> from that function seems the same as the one that is in 3.6 kernel.
> I also include the 3.6 and 3.7 kernel dmesg. The black screen is 100%
> reproducible.
>
> Any suggestion how to further debug this i9515 black screen problem?
> I really want to get it fixed.

Sorry for missing out on this one, I'll add a few more mailing lists to.

Backlight issues themselves are usually a pain. I've looked through
your debug dmesg and there doesn't seem to be anything bad going on.

Two things to test:
- Can you please check whether any of the backlight drivers in
/sys/class/backlight does anything? You need to frob the brightness
file. Please also list all the drivers you have.
- Please grab the lates git of intel-gpu-tools and attach the output
of intel_reg_dumper for both a working and a broken kernel. The git
tree is at:

http://cgit.freedesktop.org/xorg/app/intel-gpu-tools/

Since backlight bugs usually take a lot of poking to figure out it
might be good to keep things together in a bugzilla report.
bugs.freedesktop.org, DRI -> DRM (Intel) is the preferred location,
please file a report there and attach the dump files (and the debug
dmesg logs we've gathered already).

Thanks, Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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