[Patch] i915gm: framebuffer compression+tiling on exa

Peter Clifton pcjc2 at cam.ac.uk
Thu Nov 1 17:33:57 PDT 2007

On Thu, 2007-11-01 at 12:11 -0700, Jesse Barnes wrote:
> On Thursday, November 01, 2007 11:45 Pierre Willenbrock wrote:
> > Hi list,
> >
> > i am using latest git of xserver, xf86-video-intel, drm and mesa.
> > Since the merge of bufferobjects and support code into drm and
> > xf86-video-intel, i was unable to use tiling. After looking at bug
> > #12994 i found that i tried to disable framebuffer compression by
> > disabling the option "Compression" instead of
> > "FramebufferCompression", so i tried again, and found that i could
> > use either framebuffer compression or tiling, but not both.
> >
> > Digging deeper into the driver sources, i found #define
> > FBC_CTL_FENCENO, which was not used anywhere. So i tried adding the
> > fence number of my frambuffer(3) to the FBC control register, which
> > made the FBC and tiling work at the same time. A patch is attached.
> Ah, excellent!  That definitely explains the bad behavior several people 
> have been seeing.  Earlier (I think I even had a comment to this effect 
> at one point) I assumed that the front buffer was using fence 0.  This 
> looks like a real fix.  I'll go ahead and check it in.

Sorry to be annoying, but do you mind quickly explaining what "bad
behaviour" this results in? (IE. is it a fix we need to backport for
Ubuntu to fix bugs users might hit?)

Peter Clifton

Electrical Engineering Division,
Engineering Department,
University of Cambridge,
9, JJ Thomson Avenue,

Tel: +44 (0)7729 980173 - (No signal in the lab!)

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