This might be a Dave thing and not an Andi thing.
In my usual -mm-testing I only test X on the one machine (the Vaio,
natch). Check that it runs glxgears, check suspend/resume to mem and disk.
It has intel graphics and I'm not seeing any such problems.
Have you time to bisect it?
http://www.zip.com.au/~akpm/linux/patches/stuff/bisecting-mm-trees.txt
describes how.
As a quick test, perhaps build a tree with just
2.6.23-rc6+origin.patch+git-drm.patch? Fortunately git-agpgart.patch is
presently empty.
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