3.15-rc2: i915 regression: only top 20% of screen works in X

[Chris Wilson]

On Thu, Apr 24, 2014 at 03:43:45PM +0200, Pavel Machek wrote:
> Hi!
> 
> > Like Chris said please test latest drm-intel-nighlty from
> > http://cgit.freedesktop.org/drm-intel to make sure that the recently
> > merged mitigation measures work properly. But those won't get your gpu
> > back, only the display and it's only for 3.16. We're still hunting a
> 
> What does it means "won't get my gpu back, just my display"? Gpu is
> the thing driving the display... no?

We think of it as discrete functional units, i.e. the display engine is
separate from the GPU. What happens here is that the render engine
doesn't respond to our commands to set it up, but that should not
prevent us from setting the register values in the display engine to drive
the actual outputs.
 
> I checked out drm-intel-nightly. Now I can see some kernel messages
> scrolling around on vga console (improvement?), but then end up with
> completely blank screen, and dead machine, AFAICT. Can't seem to ping
> it.

Eeek. Do you have netconsole handy?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre