Greg KH wrote:
> On Sat, Nov 18, 2017 at 01:47:32PM +0100, Rainer Fiebig wrote:
>> Hi!
>>
>> Hopefully the right addressee.
>>
>> Encountered two bad backports which cause screen-flicker.
>> dmesg shows:
>>
>> ...
>> [drm:ironlake_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
>> [drm:ironlake_irq_handler [i915]] *ERROR* PCH transcoder A FIFO underrun
>> [drm:ironlake_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun
>> [drm:ironlake_irq_handler [i915]] *ERROR* PCH transcoder B FIFO underrun
>> ...
>>
>> CPU: Intel Core i3 (Clarkdale/Ironlake)
>>
>> The backports are:
>>
>> - diff --git a/drivers/gpu/drm/i915/intel_pm.c
>> b/drivers/gpu/drm/i915/intel_pm.c
>> index 49de476..277a802 100644
>> - diff --git a/drivers/gpu/drm/i915/intel_drv.h
>> b/drivers/gpu/drm/i915/intel_drv.h
>> index a19ec06..3ce9ba3 100644
>>
>> After reversing them the flicker is gone, no more messages in dmesg. All
>> else OK so far.
>
> So which commit was the one that caused the problem? I will be glad to
> revert it.
>
> thanks,
>
> greg k-h
>
>
I started by reverting the more complex one first ("index
49de476..277a802100644"). But the kernel wouldn't compile then.
So I also reverted "index a19ec06..3ce9ba3 100644". After that the
kernel compiled just fine and the problems were gone (still are).
I haven't yet tried it vice versa - it was a bit late yesterday. But
I'll give it a try somewhat later today and let you know.
Personally, I could live without *both* of them.
So long!
Rainer Fiebig