I get huge amounts of flickering when abusing the 2.6.35rc kernels later than 2.6.35-rc3-git4 when using kwin, including 2.6.35-rc4-git4. This does not happen when downgrading to 2.6.35. Something applied after 2.6.35-rc3-git4 seems to be the problem.
abUsing Gentoos latest libdrm + xf86-video-ati + mesa and the x11 9999 git overlay makes no difference, IT'S THE KERNEL.
I have the same problem using the drm-radeon-testing branch of the kernel. Except i experience the problem with compiz and the task-switcher.
And i had a similar problem with the XBMC. After disabling vsync, the flickering disappeared.
ArchLinux with libdrm-git, mesa-git and xf86-video-ati-git with a HD4850.
(In reply to comment #1)
> I have the same problem using the drm-radeon-testing branch of the kernel.
> Except i experience the problem with compiz and the task-switcher.
> And i had a similar problem with the XBMC. After disabling vsync, the
> flickering disappeared.
See bug 28341 - there's no synchronization between the X and Mesa drivers to defer rendering to buffers involved in a pending vsynced buffer swap, so you sometimes see an incomplete next frame.
However, AFAICT the kernel support for the broken functionality already went into 2.6.35-rc1, so I'm not sure this is the same bug... Øyvind, can you try bisecting the kernel for your problem?
Works fine 2.6.35-git2 + current git drm+ati+mesa