I attached a netconsole capture, maybe it helps.

I set the following kernel command line options

radeon.dpm=1 ignore_loglevel drm.debug=14

drm.debug=15 had too much output, dozens of lines per second.

It doesnt have the boot part because i had to enable netconsole runtime as i
use a bridge and it comes up after netconsole wants to begin logging (if i use
eth0 it logs until br0 comes up) if i use the kernel command line to set up
netconsole.

I have a 17" LCD Monitor connected to the CRT1 connector.