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We need to wait for the GPUVM flush to complete. There was some confusion as to how this mechanism was supposed to work. The operation is not atomic. For GPU initiated invalidations you need to read back a VM register to introduce enough latency for the update to complete. v2: drop gart changes v3: just read back rather than polling Reviewed-by: Christian König <christian.koenig@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Cc: stable@vger.kernel.org