[PATCH] [RFC] dix/mi: remove ChangeWindowAttributes from rendering path.

[Aaron Plattner]

On Mon, Apr 04, 2011 at 01:24:10PM -0700, Dave Airlie wrote:
> > Are you planning on leaving the ChangeWindowAttrbutes screen hook there, or
> > is it slated for deletion?  I ask because we currently wrap CWA so we can
> > watch for colormap changes on PseduoColor windows.
> >
> 
> Can you give me a why?

ftp://download.nvidia.com/XFree86/Linux-x86/270.30/README/xconfigoptions.html#cioverlay

When the colormap changes, we need to flush the updates through to the
hardware.

> What does the driver do with this information later, is it an
> optimisation or a requirement etc.

It's a requirement -- we need a callback when the colormap changes, and we
need the WindowPtr so we can get at the private data we hang off of it so
we can know what needs updating.

> You can consider anything that passes a WindowPtr into the
> driver/acceleration layers
> on my hit list for removal at some point in the future, I'm sure we'll
> find a few wtf cases but
> I'm hoping to solve them.

We also hook heavily into the ValidateTree series of calls because properly
sequencing window moves with asynchronous OpenGL clients is hard,
especially with Xinerama in the picture.  I guess maybe if you want to make
Windows opaque to the graphics driver but not to extensions, we could
marshal that stuff through our GLX extension module.  Still, we have more
than a decade's worth of bug fixes in that area and it would make me really
nervous to try to rearrange that stuff.