https://bugzilla.kernel.org/show_bug.cgi?id=71891
--- Comment #14 from Christian König deathsimple@vodafone.de --- (In reply to sdh from comment #13)
Can you suggest me a good way to debug this and read the logs? Everything hangs up, so I do a hard reboot and start with nomodeset parameter to see the logs. Is there a better way to do this?
Not sure how to do it on Arch, but on Ubuntu I would but the radeon module on the blacklist and boot into text only mode.
Then SSH into the system over the network, load the radeon module manually. If that doesn't crash try to also start X manually.