Re: i915 black screen introduced by ACPI changes

[Daniel Vetter]

On Mon, Mar 4, 2013 at 6:11 PM, Chris Li <lkml@xxxxxxxxxxx> 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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