/var/log/Xorg.0.log

# cat /var/log/Xorg.0.log | grep EE

	(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[   117.803] Initializing built-in extension MIT-SCREEN-SAVER
[   117.806] (EE) Failed to load /usr/lib/xorg/modules/libglamoregl.so: /usr/lib/xorg/modules/libglamoregl.so: undefined symbol: _glapi_tls_Context
[   117.806] (EE) Failed to load module "glamoregl" (loader failed, 7)
[   117.852] (EE) open /dev/dri/card0: No such file or directory