You can see it in the Xorg.0.log for future reference -
(EE) RADEON(0): [dri] RADEONDRIGetVersion failed because of a version mismatch.
[dri] radeon.o kernel module version is 2.0.0 but version 1.17.0 or newer is needed.
[dri] Disabling DRI.
radeon.o kernel module version 2.0.0 gets loaded when you boot with KMS and requires mesa 7.6 and libdrm-radeon1 to work with DRI, it uses the lower 1.x.x version when its disabled which works with mesa 7.5 and no libdrm-radeon1.
You can see it in the Xorg.0.log for future reference -
(EE) RADEON(0): [dri] RADEONDRIGetVersion failed because of a version mismatch.
[dri] radeon.o kernel module version is 2.0.0 but version 1.17.0 or newer is needed.
[dri] Disabling DRI.
radeon.o kernel module version 2.0.0 gets loaded when you boot with KMS and requires mesa 7.6 and libdrm-radeon1 to work with DRI, it uses the lower 1.x.x version when its disabled which works with mesa 7.5 and no libdrm-radeon1.