As of the commit:
    d8d1721cfb3162abbda078d67a928792d6552b84 : A series of fixup patches meant
to fix the usage of DMA on stack, plus one warning fixup

My R9 290 produces heavy flickering artifacts in 1 of 3 or 4 cases when
starting Linux.
I am using the amdgpu kernel module, and have not tested this with radeon.
When the bug occurs, the system is completely unusable.

Since the occurence of this bug is not really deterministic, bisecting it was
not that easy. I hope I didn't make any mistake.