Re: [PATCH 7/7] drm/i915: fbdev restore mode needs to invalidate frontbuffer

Daniel Vetter
2015-07-09T15:23:44Z

On Wed, Jul 08, 2015 at 03:05:49PM -0300, Paulo Zanoni wrote:
> 2015-07-07 20:28 GMT-03:00 Rodrigo Vivi <rodrigo.vivi@intel.com>:
> > This fbdev restore mode was another corner case that was now
> > calling frontbuffer flip and flush and making we miss
> > screen updates with PSR enabled.
> >
> > So let's also add the invalidate hack here while we don't have
> > a reliable dirty fbdev op.
>
> So when I saw patches 6 and 7 I decided to investigate how fbcon
> interacts with frontbuffer tracking. One thing that I notice is that,
> without this patch, if I kill the display manager, I'll have a bunch
> of flushes without an invalidate when returning to fbcon. And I
> suppose we don't want PSR/FBC enabled on fbcon, so this patch seems to
> fix a bug.
>
> By the way, I think we can try to simulate this "kill display manager"
> bug on IGT. We could try to close the DRM device and then check if
> FBC/PSR stopped. I guess it's probably easier to create a new IGT test
> for that.

Hm yeah that would be a nice testcase indeed.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation