X11/DRI artifacts with Radeo HD 4650/RV730 Pro

[Thomas Klausner <wiz%NetBSD.org@localhost>]

Hi!

After updating to 7.99.x with the new DRM code, I see black artifacts
on the screen. These didn't happen with the old DRM code.

I haven't found out how to trigger them, because there are phases when
it works fine, and then there are phases where it happens on every
second mouse move (redraw?).

When I turn off acceleration, I haven't been able to reproduce them.

The black shapes are sometimes rectangle, but also triangles or other
patterns.
 Thomas