For me, under kernel 3.0.0-16-generic, running xrandr takes ~1.4 seconds and it appears to stall my system while running. With 3.3.0-996-generic #201202170408 from the drm-next area above, running xrandr takes ~170ms and doesn't cause my system to stall (at least noticeably). So for me, it appears the problems are gone or at least are greatly reduced.
For me, under kernel 3.0.0-16-generic, running xrandr takes ~1.4 seconds and it appears to stall my system while running. With 3.3.0-996-generic #201202170408 from the drm-next area above, running xrandr takes ~170ms and doesn't cause my system to stall (at least noticeably). So for me, it appears the problems are gone or at least are greatly reduced.