RandR 1.4 restart

James Jones jajones at nvidia.com
Tue Mar 1 18:56:36 PST 2011

On Tuesday 01 March 2011 08:02:24 Keith Packard wrote:

> Scanout pixmaps get resized automatically when the associated crtc gets
> a new mode. This lets a compositing manager deal with the scanout pixmap
> creation while separate screen configuration applications deal with mode
> setting. Of course, internally, this is done by creating a new scanout
> pixmap and pointing the existing XID at the new object. (Hrm. I wonder if
> there are implications for DRI2/GLX/EGL here...)

Yeah, I hadn't thought about that, that's a mess.  GLX has a separate name for 
the pixmap, so any GLX pixmaps are still going to refer to the old pixmap.  At 
the very least, the function that frees and reallocates the new pixmap in X 
should be wrappable, so GLX can hook in and update things.  However, this 
means drivers can no longer rely on a GLX pixmap's storage not moving after it 
is created.  I think that's handleable, but it will muddy a lot of otherwise 
clean code.

I'll try to make time to look over randr 1.4 in more depth in the next couple 
of days.


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