https://bugs.freedesktop.org/show_bug.cgi?id=106229
--- Comment #3 from Luke-Jr luke-jr+freedesktopbugs@utopios.org --- It did work with the "radeon" driver on x86, and *mostly* works with "radeon" on POWER9 as well (except that it limits itself to 32-bit DMA for some reason, and eventually crashes when I bump up against the allocation limit; to workaround that, I am currently using the fbdev Xorg driver with the radeon kernel driver).