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Subject[PATCH v8 5/8] drm/sun4i: sun6i_mipi_dsi: Add DSI hblk packet overhead
Date
Like other dsi setup timings, hblk would also require to add
packet overhead.

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/
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 6b26dba883e8..a64e6ec00f22 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
@@ -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
--
2.18.0.321.gffc6fa0e3
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