https://bugs.freedesktop.org/show_bug.cgi?id=84017
--- Comment #9 from Christoph Brill egore@gmx.de --- I played with the cmdline "radeon.msi" and couldn't get any of the PCI-MSI-edge counters to show anything else than 0. No matter which value used and no matter if any 3D operation was done.
I haven't touched "pci=nomsi". It looks like MSI is not working at all on this chipset ...