[BUG] xrandr/desktop autoconfiguration problem with Intel chip

[Adam Jackson]

On 4/10/11 6:53 PM, James Bottomley wrote:

> However, when I plug in a standard 1024x768 projector, it gets set up
> (using the standard gnome hotplug) to the right of my current display
> (giving an x dimension of 2390) and the whole of the LVDS display gets a
> dark grey shadow.  If I use xrandr to redo the tiling so LVDS1 is above
> VGA1 (giving a max y dimension of 1536) everything is fine.  I think
> this indicates that although my graphics chip seems to identify as GEN
> 3, it has trouble with display dimensions>  2048.

gen3's coordinate limits are awkward.  The 2D engine and CRTCs can 
stride up to 4096 wide, but the 3D engine can only stride up to 2048 
wide (both in terms of the widest texture it can source from, and the 
widest surface it can render to).  Thanks Intel.

This is one of the motivators for the per-CRTC pixmap work planned for 
RANDR 1.4.  It'll require a modest amount of work in the compositor to 
take advantage of, but once complete we should be able to hide this kind 
of detail from you.  In the meantime if you've got a >2048 wide screen 
on gen3 you're basically out of luck for GL-based compositors.

- ajax