Re: [Intel-gfx] Skylake graphics regression: projector failure with 4.8-rc3

From: Jani Nikula
Date: Tue Sep 20 2016 - 04:14:54 EST

On Mon, 19 Sep 2016, James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote:
> On Mon, 2016-09-19 at 08:09 -0700, James Bottomley wrote:
>> On Sun, 2016-09-18 at 13:35 +0200, Thorsten Leemhuis wrote:
>> > Hi! James & Paulo: What's the current status of this?
>> No, the only interaction has been the suggestion below for a revert,
>> which didn't fix the problem.
>> > Was this issue discussed elsewhere or even fixed in between? Just
>> > asking, because this issue is on the list of regressions for 4.8.
>> I'm just about to try out -rc7, but it's not fixed so far.
> OK, with -rc7 and the i915 fixes, there seems to be a marked
> improvement. I can no longer crash the crtc by using lots of xrandr
> switches, which was the principal problem.
> I've so far only got one of these in the logs
> [14858.635035] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR*
> CPU pipe B FIFO underrun
> And the only residual problem seems to be that the monitor goes blank
> periodically, but this can be fixed by switching resolution a couple of
> times.
> I haven't seen any of the link training errors so far and I've run
> through my usual battery of be nasty to the external monitor tests.

Thanks for the update. We still have fixes for the underruns in the


Jani Nikula, Intel Open Source Technology Center