Bug 103796

Summary:	4.9.62: intermittent flicker after upgrade from 4.9.61
Product:	DRI	Reporter:	Rainer Fiebig <jrf>
Component:	DRM/Intel	Assignee:	Intel GFX Bugs mailing list <intel-gfx-bugs>
Status:	CLOSED NOTOURBUG	QA Contact:	Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity:	major
Priority:	medium	CC:	intel-gfx-bugs
Version:	XOrg git
Hardware:	x86-64 (AMD64)
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:

Description Rainer Fiebig 2017-11-17 16:44:59 UTC

After upgrading from 4.9.61 there's an intermittent flicker when entering the first character in a terminal, editor, input-box or even randomly without any action from my side.

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

Can't bisect this at the moment but I've seen this before: https://bugs.freedesktop.org/show_bug.cgi?id=97283
 
A bad i915-related backport, I think.

Comment 1 Rainer Fiebig 2017-11-17 23:07:02 UTC

Yes, it's the i915-backports that cause the problem:

- 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 *both* (else the kernel won't compile) the flicker is gone, no more messages in dmesg. 

4.4 is also unusable with those processors b/c of i915-problems (https://bugs.freedesktop.org/show_bug.cgi?id=99737).


And I have a premonition now concerning 4.14. ;)

Comment 2 Rainer Fiebig 2017-11-19 14:58:29 UTC

As this matter seems specific to LTS-kernel 4.9, I had also reported this at kernel.org. We're working on a solution there.

So, AFAIC you may close this report.

BTW: 4.14 is not affected.

So long!
Rainer Fiebig

Comment 3 Elizabeth 2017-11-21 16:08:10 UTC

(In reply to Rainer Fiebig from comment #2)
> As this matter seems specific to LTS-kernel 4.9, I had also reported this at
> kernel.org. We're working on a solution there.
> 
> So, AFAIC you may close this report.
> 
> BTW: 4.14 is not affected.
> 
> So long!
> Rainer Fiebig
Thanks for the information Rainer, closing then. Do you mind sharing the link of the bug at kernel.org in case someone looks for the issue here. Thank you again.

Comment 4 Rainer Fiebig 2017-11-21 16:38:40 UTC

bugzilla-daemon@freedesktop.org wrote:
> Elizabeth <mailto:elizabethx.de.la.torre.mena@intel.com> changed bug
> 103796 <https://bugs.freedesktop.org/show_bug.cgi?id=103796>
> What 	Removed 	Added
> Status 	NEW 	RESOLVED
> Resolution 	--- 	NOTOURBUG
> 
> *Comment # 3 <https://bugs.freedesktop.org/show_bug.cgi?id=103796#c3> on
> bug 103796 <https://bugs.freedesktop.org/show_bug.cgi?id=103796> from
> Elizabeth <mailto:elizabethx.de.la.torre.mena@intel.com> *
> 
> (In reply to Rainer Fiebig from comment #2 <show_bug.cgi?id=103796#c2>)
>> As this matter seems specific to LTS-kernel 4.9, I had also reported this at > kernel.org. We're working on a solution there. > > So, AFAIC you may
> close this report. > > BTW: 4.14 is not affected. > > So long! > Rainer
> Fiebig
> Thanks for the information Rainer, closing then. Do you mind sharing the link
> of the bug at kernel.org in case someone looks for the issue here. Thank you
> again.
> 
> ------------------------------------------------------------------------
> You are receiving this mail because:
> 
>   * You reported the bug.
> 

It's an email-thread at stable@vger.kernel.org, look for same re:

Cheers!

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