Re: 4.9.62: intermittent flicker after upgrade from 4.9.61

[Greg KH <gregkh@linuxfoundation.org>]

On Sat, Nov 18, 2017 at 05:08:20PM +0100, Rainer Fiebig wrote:
> 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.

What git commit id is that?  I don't see those ids in the 4.9-stable
tree.

> So I also reverted "index a19ec06..3ce9ba3 100644". After that the
> kernel compiled just fine and the problems were gone (still are).

Same here, what git commit id was this?

thanks,

greg k-h