drm/tegra: dsi: Use proper back-porch for non-sync video mode
In video modes without sync pulses, the horizontal back-porch needs to
include the horizontal sync width.
Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/gpu/drm/tegra/dsi.c b/drivers/gpu/drm/tegra/dsi.c
index ed970f6..5c489c2 100644
--- a/drivers/gpu/drm/tegra/dsi.c
+++ b/drivers/gpu/drm/tegra/dsi.c
@@ -548,14 +548,19 @@
/* horizontal sync width */
hsw = (mode->hsync_end - mode->hsync_start) * mul / div;
- hsw -= 10;
/* horizontal back porch */
hbp = (mode->htotal - mode->hsync_end) * mul / div;
- hbp -= 14;
+
+ if ((dsi->flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE) == 0)
+ hbp += hsw;
/* horizontal front porch */
hfp = (mode->hsync_start - mode->hdisplay) * mul / div;
+
+ /* subtract packet overhead */
+ hsw -= 10;
+ hbp -= 14;
hfp -= 8;
tegra_dsi_writel(dsi, hsw << 16 | 0, DSI_PKT_LEN_0_1);