diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 1438a4b..99014d7 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3352,6 +3352,8 @@ static uint32_t skl_wm_method2(uint32_t pixel_rate, uint32_t pipe_htotal,
                plane_bytes_per_line *= 4;
                plane_blocks_per_line = DIV_ROUND_UP(plane_bytes_per_line, 512);
                plane_blocks_per_line /= 4;
+       } else if (tiling == DRM_FORMAT_MOD_NONE) {
+               plane_blocks_per_line = DIV_ROUND_UP(plane_bytes_per_line, 512) + 1;
        } else {
                plane_blocks_per_line = DIV_ROUND_UP(plane_bytes_per_line, 512);
        }