Now, after some package updates, i can no longer reproduce the strange behaviour where user can't use the proper driver and root can. That issue is fixed on my notebook. Still, some trouble remains: $ dmesg | grep error
[ 15.539757] render error detected, EIR: 0x00000010 [ 15.539764] [drm:i915_handle_error] *ERROR* EIR stuck: 0x00000010, masking [ 15.539785] render error detected, EIR: 0x00000010
Now, after some package updates, i can no longer reproduce the strange behaviour where user can't use the proper driver and root can. That issue is fixed on my notebook.
Still, some trouble remains:
$ dmesg | grep error
[ 15.539757] render error detected, EIR: 0x00000010 handle_ error] *ERROR* EIR stuck: 0x00000010, masking
[ 15.539764] [drm:i915_
[ 15.539785] render error detected, EIR: 0x00000010