Comment # 2 on bug 73530 from Paul Menzel

Created attachment 91918 [details]
Linux kernel ring buffer (`dmesg`)

Please note the Linux kernel command line, which has `radeon.modeset=0`,
`drm.debug=14` and `acpi_osi=Linux`. Later the the Radeon module is removed
with `sudo modprobe -r radeon` and reloaded with `sudo modprobe radeon
modeset=1`.