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
OK, no mistake. IIRC, I took the patches (and the IDs) from the changelog for patch-4.9.62. I've attached both, so you can check yourself.
I've also applied a freshly downloaded patch-4.9.62 to a freshly expanded 4.9 and re-compiled. The flicker is there. I haven't yet reverted the two patches but I'm confident that after having done so the flicker will be gone. If not I'll let you know.
As a good news: 4.14 is *not* affected. So to me it seems those two patches are part of sort of a package and can not be backported alone.
So long! Rainer Fiebig