The value was much too low, which could cause the userspace visible vblank counter to move backwards when the hardware counter wrapped around. Ported from radeon commit: b0b9bb4dd51f396dcf843831905f729e74b0c8c0 Reviewed-by: Christian König <christian.koenig@amd.com> Reviewed-by: Jammy Zhou <Jammy.Zhou@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Cc: stable@vger.kernel.org