commit 83da6eea3af669ee0b1f1bc05ffd6150af984994 upstream. To avoid underflow seen on Polaris10 with some 3440x1440 144Hz displays. As the threshold of 190 us cuts too close to minVBlankTime of 192 us. Signed-off-by: Evan Quan <evan.quan@amd.com> Acked-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>