lkml.org 
[lkml]   [2019]   [Feb]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v8 2/8] drm/sun4i: sun6i_mipi_dsi: Fix DSI hbp timing value
Date
Current driver is calculating hbp maximum value by subtracting
hsync_start with hdisplay which is front porch value, but the
hbp refers to back porch.

Back porch value is calculating by subtracting htotal with
hsync_end as per drm_mode timings, and BSP code from BPI-M64-bsp
is eventually following the same.

BPI-M64-bsp is computing hbp as
(in drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c)
dsi_hbp = (hbp-hspw)*dsi_pixel_bits[format]/8 - (4+2);
=> (panel->lcd_hbp - timmings->hor_sync_time)
=> (timmings->hor_back_porch + timmings->hor_sync_time -
timmings->hor_sync_time)
=> timmings->hor_back_porch
=> mode->htotal - mode->hsync_end

So, update the hbp value accordingly in sun6i_dsi_setup_timings.

Tested on 2-lane, 4-lane DSI LCD panels.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Merlijn Wajer <merlijn@wizzup.org>
---
drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
index d70a8c43a4b8..982ae6b17654 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
@@ -472,7 +472,7 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi,
*/
#define HBP_PACKET_OVERHEAD 6
hbp = max((unsigned int)HBP_PACKET_OVERHEAD,
- (mode->hsync_start - mode->hdisplay) * Bpp - HBP_PACKET_OVERHEAD);
+ (mode->htotal - mode->hsync_end) * Bpp - HBP_PACKET_OVERHEAD);

/*
* The frontporch is set using a blanking packet (4 bytes +
--
2.18.0.321.gffc6fa0e3
\
 
 \ /
  Last update: 2019-02-14 20:26    [W:0.064 / U:13.812 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site