https://bugs.freedesktop.org/show_bug.cgi?id=101691

--- Comment #37 from Michel Dänzer michel@daenzer.net --- I wonder if it could be related to the caching attributes of the system memory pages being shared between the GPUs. AFAICT the amdgpu driver should end up treating them as non-cacheable, and correspondingly program the AMD GPU not to participate in cache coherency protocol for them. How does the i915 driver treat the pages of imported buffer objects?