[REGRESSION] Re: i915 driver crashes on T540p if docking station attached

Daniel Vetter daniel at ffwll.ch
Mon Aug 3 15:05:14 PDT 2015

On Mon, Aug 3, 2015 at 7:24 PM, Linus Torvalds
<torvalds at linux-foundation.org> wrote:
>>                      However, I'm
>> still seeing a large number of drm/i915 related warning messages and
>> other kernel kvetching.
> I suspect I can live with that for now. The lockdep one looks like
> it's mainly an initialization issue, so you'd never get the actual
> deadlock in practice, but it's obviously annoying.  The intel_pm.c one
> I'll have to defer to the i915 people for..

The lockdep splat is just acpi being inconsistent with init_mutex vs.
backlight notifier_chain (which has it's own lock) calls. init_mutex
is new in 4.2 and has been added in

commit 87521e16a7abbf3fa337f56cb4d1e18247f15e8a
Author: Hans de Goede <hdegoede at redhat.com>
Date:   Tue Jun 16 16:27:48 2015 +0200

    acpi-video-detect: Rewrite backlight interface selection logic

Not mine ;-) But adding relevant people.

I'll send you a pull for the mst one tomorrow and look into the
watermark fail in intel_pm.c too.
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

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