According to horizontal and vertical timings are defined per the diagram from include/drm/drm_modes.h Back porch = [hv]total - [hv]sync_end So, update SUN6I_DSI_BASIC_SIZE0_VBP calculation as mode->vtotal - mode->vsync_end Signed-off-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c index 1c7e42015645..599284971ab6 100644 --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c @@ -526,8 +526,8 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi, regmap_write(dsi->regs, SUN6I_DSI_BASIC_SIZE0_REG, SUN6I_DSI_BASIC_SIZE0_VSA(mode->vsync_end - mode->vsync_start) | - SUN6I_DSI_BASIC_SIZE0_VBP(mode->vsync_start - - mode->vdisplay)); + SUN6I_DSI_BASIC_SIZE0_VBP(mode->vtotal - + mode->vsync_end)); regmap_write(dsi->regs, SUN6I_DSI_BASIC_SIZE1_REG, SUN6I_DSI_BASIC_SIZE1_VACT(mode->vdisplay) | -- 2.18.0.321.gffc6fa0e3