From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Icenowy Zheng <icenowy@aosc.io>

Date: Mon, 16 Mar 2020 21:35:02 +0800

Subject: [PATCH] drm/sun4i: sun6i_mipi_dsi: fix horizontal timing calculation

The max() function call in horizontal timing calculation shouldn't pad a

length already subtracted with overhead to overhead, instead it should

only prevent the set timing to underflow.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>

---

 drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 10 +++++-----

 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c

index aa67cb037e9d..52e009dc632b 100644

--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c

+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c

@@ -556,7 +556,7 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi,

 		 */

 #define HSA_PACKET_OVERHEAD	10

 		hsa = max((unsigned int)HSA_PACKET_OVERHEAD,

-			  (mode->hsync_end - mode->hsync_start) * Bpp - HSA_PACKET_OVERHEAD);

+			  (mode->hsync_end - mode->hsync_start) * Bpp) - HSA_PACKET_OVERHEAD;

 		/*

 		 * The backporch is set using a blanking packet (4

@@ -565,7 +565,7 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi,

 		 */

 #define HBP_PACKET_OVERHEAD	6

 		hbp = max((unsigned int)HBP_PACKET_OVERHEAD,

-			  (mode->htotal - mode->hsync_end) * Bpp - HBP_PACKET_OVERHEAD);

+			  (mode->htotal - mode->hsync_end) * Bpp) - HBP_PACKET_OVERHEAD;

 		/*

 		 * The frontporch is set using a sync event (4 bytes)

@@ -575,7 +575,7 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi,

 		 */

 #define HFP_PACKET_OVERHEAD	16

 		hfp = max((unsigned int)HFP_PACKET_OVERHEAD,

-			  (mode->hsync_start - mode->hdisplay) * Bpp - HFP_PACKET_OVERHEAD);

+			  (mode->hsync_start - mode->hdisplay) * Bpp) - HFP_PACKET_OVERHEAD;

 		/*

 		 * The blanking is set using a sync event (4 bytes)

@@ -584,8 +584,8 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi,

 		 */

 #define HBLK_PACKET_OVERHEAD	10

 		hblk = max((unsigned int)HBLK_PACKET_OVERHEAD,

-			   (mode->htotal - (mode->hsync_end - mode->hsync_start)) * Bpp -

-			   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

-- 

2.28.0