[PATCH] shadow: Optimize shadowUpdatePacked(). (#26973)

[Jonathan Morton]

On Wed, 2010-09-22 at 10:19 -0400, Adam Jackson wrote:
> In related news, we never fixed this:
> 
> http://lists.freedesktop.org/archives/xorg/2010-February/049026.html

IIRC, the software path for CopyArea is pretty poor and makes things
very slow if you scroll in a nontrivial direction on an unaccelerated
server.  However it does seem to avoid that bug by detecting the
nontrivial cases and using a temporary scanline buffer.

The right solution is probably to implement an overlap-capable CopyArea
routine in Pixman and have CopyArea call it when possible.

-- 
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From: Jonathan Morton
      jonathan.morton at movial.com