https://bugs.freedesktop.org/show_bug.cgi?id=41668
--- Comment #19 from Alex Deucher agd5f@yahoo.com 2011-12-15 07:19:31 PST --- (In reply to comment #18)
And finally: Is it a proper fix, or just a workaround?
It's a workaround. Since those options work, it's not a radeon bug. It's most likely a platform bug for your board; probably a bad apic or msi setup for your chipset. You might need an apic or pci quirk for your motherboard chipset.