[PATCH xserver] dri2: Invalidate DRI2 buffers for all windows with the same pixmap on swap.

[Ville Syrjälä]

On Fri, Mar 25, 2011 at 12:35:37PM +0100, ext Michel Dänzer wrote:
> From: Michel Dänzer <daenzer at vmware.com>
> 
> Without this, when a compositing manager unredirects a fullscreen window which
> uses DRI2 and page flipping, the DRI2 buffer information for the compositing
> manager's output window (typically the Composite Overlay Window or root window)
> may become stale, resulting in all kinds of hilarity.

Make sense to me.

BTW I'm toying around with offscreen flipping, and for that I'm using
the following patch to also invalidate the window's pixmap (the patch
is against our internal codebase which has the DRI2 ref counting
patches from Pauli and Christopher).