[PATCH v8 5/8] drm/sun4i: sun6i_mipi_dsi: Add DSI hblk packet overhead
From: Jagan Teki
Date: Thu Feb 14 2019 - 14:26:31 EST
Like other dsi setup timings, hblk would also require to add
Add 10 bytes packet overhead for hblk, so the blank is set using
a blanking packet like (4 bytes + 4 bytes + payload + 2 bytes)
The value 10 bytes are refereed from Allwinner BSP like how other
dsi setup timings grabs in existing driver.
This is according to BSP code from BPI-M64-bsp (from linux-sunxi/
dsi_hblk = (ht-hspw)*dsi_pixel_bits[format]/8-(4+4+2);
So, add 10 bytes packet overhead for DSI hblk.
Tested on 2-lane, 4-lane MIPI-DSI LCD panels.
Signed-off-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>
drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
index 6b26dba883e8..a64e6ec00f22 100644
@@ -485,8 +485,13 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi,
* hblk seems to be the line + porches length.
+ * The blank is set using a blanking packet (4 bytes + 4 bytes +
+ * payload + 2 bytes). So minimal size is 10 bytes
- hblk = (mode->htotal - (mode->hsync_end - mode->hsync_start)) * Bpp;
+#define HBLK_PACKET_OVERHEAD 10
+ hblk = max((unsigned int)HBLK_PACKET_OVERHEAD,
+ (mode->htotal - (mode->hsync_end - mode->hsync_start)) *
+ Bpp - HBLK_PACKET_OVERHEAD);
* And I'm not entirely sure what vblk is about. The driver in