Re: 4.9.62: intermittent flicker after upgrade from 4.9.61

[Rainer Fiebig <jrf@mailbox.org>]

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
> 

OK, when reversing only "index 49de476..277a802 100644" the kernel
doesn't compile.

When reversing only "index a19ec06..3ce9ba3 100644" the kernel compiles
but the flicker is there.

Seems those patches are a nasty couple that needs to be removed as such. ;)

So long!
Rainer Fiebig