https://bugs.freedesktop.org/show_bug.cgi?id=102500
--- Comment #20 from charlie bug0xa3d2@hushmail.com --- I confirm that bug 102500 and bug 102598 are the same.
I split up the patch into 3 parts and they applied cleanly with offsets to drm-next-4.15-wip.
I then reverted mesa to commit 214b565bc28bc4419f3eec29ab7bbe34080459fe (winsys/amdgpu: set AMDGPU_GEM_CREATE_VM_ALWAYS_VALID if possible v2) compiled and started X and corruption and lockups are gone.