72a9987edc
This ensures the GPU sees all previous CPU writes to VRAM, which makes it safe: * For userspace to stream data from CPU to GPU via VRAM instead of GTT * For IBs to be stored in VRAM instead of GTT * For ring buffers to be stored in VRAM instead of GTT, if the HPD flush is performed via MMIO Signed-off-by: Michel Dänzer <michel.daenzer@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>