[Intel-gfx] v3.12 does not work on ByT-I

[Jesse Barnes]

On Thu, 7 Nov 2013 20:21:19 +0800
"Bityutskiy, Artem" <artem.bityutskiy at intel.com> wrote:

> Hi,
> 
> Tizen IVI does not boot to UI anymore on ByT-I boards with kernel 3.12,
> just like with 3.12-rc1, rc2, etc. v3.11 works fine.
> 
> I tried to enable drm.debugging, but could not figure out what is going
> wrong. I've attached one debug log (drm.debug=0xFF). I can lessen the
> verbosity if needed.
> 
> Anyway, I've bisected it, and found out that this commit fixes our
> problem:
> 
> 0b6279520519 drm/i915/vlv: re-enable hotplug detect based probing on VLV/BYT
> 
> Jesse, Daniel, any idea what is the issue and why this patch fixes it?
> The thing is that Tizen IVI boots to UI just fine with 3.12 plus this
> patch, while stock 3.12 does not work.
> 
> We also have this bug-report about the problem:
> https://bugs.tizen.org/jira/browse/TIVI-2085
> 
> Are OK sending this patch to GregKH / stable for 3.12.x inclusion?

Hm, I wonder if this bug is also related to the backlight stuff Jani
recently pushed fixes for.  It looks like you have an eDP panel here,
but if for some reason it got bounced between two CRTCs due to bad
detection on one, it could cause a blank screen issue.

commit 07bf139b906013ecef0c5e0441564d1ae10e974a
Author: Jesse Barnes <jbarnes at virtuousgeek.org>
Date:   Thu Oct 31 18:55:50 2013 +0200

    drm/i915/vlv: use per-pipe backlight controls v2

commit 752aa88a1e784c22d514db3b440e49427b58259e
Author: Jesse Barnes <jbarnes at virtuousgeek.org>
Date:   Thu Oct 31 18:55:49 2013 +0200

    drm/i915: make backlight functions take a connector


commit 91a60f20712179e56b7a6c3d332a5f6f9a54aa11
Author: Jani Nikula <jani.nikula at intel.com>
Date:   Thu Oct 31 18:55:48 2013 +0200

    drm/i915: move opregion asle request handling to a work queue

are the relevant commits.

Jesse