Comment # 4 on bug 73530 from Alex Deucher

(In reply to comment #2)
> 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`.

I don't seen any radeon messages.  It doesn't look like it loaded properly.