When I was debugging some DMA API accounting error (which were found to be with the DMA API debug code), I encountered a couple of issues: 1). Doing "unbind" on the PCI device would crash the kernel _only_ with the nouveau driver. The readon worked fine. This was due to: "drm/ttm: callback move_notify any time bo.." and reverting that fixed it.
2). Extreme slowness when moving the cursor madly around. This was due to the nouveau driver calling the unpopulate (now that unbind + unpopulate are squashed) quite a lot (this is using Gnome Shell - I think GNOME2 did not have those issues but I can't recall). Radeon did not have these issues.
Anyhow these patches fix the 50% perf regression I saw on nouveau and also some minor bugs that I noticed. Please apply.
Thomas asked me to also do some perf results on AGP hardware (both nouveau and radeon) and I am going to do that this week - any pointers of what is a good game/OpenGL application to run a time-based benchmark?