drmCheckModesettingSupported fails if X loaded radeon modeset=1 just before
Submitted by Brice Goglin @bgoglin
Assigned to xf86-video-ati maintainers
Description
If using KMS without loading radeon automatically during boot, X loads the radeon kernel module at startup but drmCheckModesettingSupported fails. It looks like drm sysfs files are not setup yet when drmCheckModesettingSupported runs. My understanding is that X loads the radeon kernel module but it doesn't wait long enough before trying to use what radeon is setting up in the kernel and sysfs.
So X starts without enabling KMS support, which works but disables DRI2. Then if I restart X, drm files are already setup, so KMS/DRI2 gets enabled this time, but the display gets screwed up...
If I load radeon during boot, or if I load it manually before starting X, everything looks good.
This is a Thinkpad T43 with rv370. Running Linux 2.6.32 (from Debian sid, with RADEON_KMS not set), libdrm 2.4.16 with radeon experimental api enabled, Xserver 1.7.3, xf86-video-radeon git master from yesterday, and Mesa 7.6.1-rc3.