Greg KH wrote: > 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 > Please wait a moment. I'm checking whether I've made a mistake here.