[Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

[Daniel Vetter]

On Fri, Jun 24, 2016 at 01:42:06PM +0100, Chris Wilson wrote:
> On Fri, Jun 24, 2016 at 12:48:17PM +0100, Steven Newbury wrote:
> > On Fri, 2016-06-24 at 11:59 +0100, Chris Wilson wrote:
> > > On Thu, Jun 23, 2016 at 02:14:12PM +0100, Steven Newbury wrote:
> > > > On Thu, 2016-06-23 at 15:59 +0300, Jani Nikula wrote:
> > > > > On Thu, 23 Jun 2016, Steven Newbury <steve at snewbury.org.uk>
> > > > > wrote:
> > > > > > I'm seeing this on my IvyBridge.  I'll try reverting the commit
> > > > > > here
> > > > > > too, to see if it's the same issue.
> > > > > 
> > > > > IvyBridge doesn't have low vswing for eDP. If reverting helps,
> > > > > it's a
> > > > > different failure mode.
> > > > > 
> > > > It must be something else then.  Actually, in my case linus/master
> > > > is
> > > > okay.  I saw the subject and though it must be the same issue.  I'm
> > > > seeing it with drm-intel nightly/next branches.  Shall I try to
> > > > bisect
> > > > it?  Symptoms are similar, although I would describe it more like
> > > > flashes of a different buffer across parts of the screen.
> > > 
> > > Try reverting ee042aa40b66d18d465206845b0752c6a617ba3f instead.
> > > -Chris
> > > 
> > 
> > Yes, thanks, that "fixed" it.  So atomic commits not working properly
> > on IVB?
> 
> Not yet it seems. Something seems to be off in the timing, but has so
> far eluded capture.

Fyi we reverted this for now to fix things up:

commit 527b6abe5fd2d24fba69e9564a2d608e1796ca8d
Author: Chris Wilson <chris at chris-wilson.co.uk>
Date:   Fri Jun 24 13:44:03 2016 +0100

    Revert "drm/i915: Use atomic commits for legacy page_flips"

Kudos to Chris for handling this in my absence.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch