The formula in the BSP kernel indicates that a 16-byte overhead is used
when sending the HFP. However, this value is currently set to 6 in the
sun6i_mipi_dsi driver, which makes some panels flashing.
Fix this overhead value.
Signed-off-by: Icenowy Zheng <icen...@aosc.io>
---
drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
index b8a0d0501ca7..8fe8051c34e6 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
@@ -569,11 +569,12 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi,
(mode->htotal - mode->hsync_end) * Bpp -
HBP_PACKET_OVERHEAD);
/*
- * The frontporch is set using a blanking packet (4
- * bytes + payload + 2 bytes). Its minimal size is
- * therefore 6 bytes
+ * The frontporch is set using a sync event (4 bytes)
+ * and two blanking packets (each one is 4 bytes +
+ * payload + 2 bytes). Its minimal size is therefore
+ * 16 bytes
*/
-#define HFP_PACKET_OVERHEAD 6
+#define HFP_PACKET_OVERHEAD 16
hfp = max((unsigned int)HFP_PACKET_OVERHEAD,
(mode->hsync_start - mode->hdisplay) * Bpp -
HFP_PACKET_OVERHEAD);
--
2.21.0
