modesetting: Disable atomic support by default
The atomic driver has issues with modesetting when stealing connectors from a different crtc, a black screen when doing rotation on a different crtc, and in general is just a mapping of the legacy helpers to atomic. This is already done in the kernel, so just fallback to legacy by default until this is fixed.
Please backport to 1.20, as we don't want to enable it for everyone there. It breaks for existing users.
The fixes to make the xserver more atomic have been pending on the mailing list for ages.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110375 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110030 References: !36 (commits) Signed-off-by: Maarten Lankhorst firstname.lastname@example.org