[PATCH v5 10/17] drm/sun4i: sun6i_mipi_dsi: Add DSI hblk packet overhead

Jagan Teki
2018-12-10T16:18:07Z

Add 10 bytes packet overhead for hblk where blank is set using
a blanking packet like (4 bytes + 4 bytes + payload + 2 bytes)

This is according to BSP code from BPI-M64-bsp (from linux-sunxi/
drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c)

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@amarulasolutions.com>
---
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 4c95b3384ed9..07eba9ec469b 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
@@ -494,8 +494,13 @@ 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
--
2.18.0.321.gffc6fa0e3