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Subject[PATCH 4/5] drm/sun4i: sun6i_mipi_dsi: fix horizontal timing calculation
Date
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 059939789730..5f2313c40328 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
@@ -555,7 +555,7 @@ 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
@@ -564,7 +564,7 @@ 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)
@@ -574,7 +574,7 @@ 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)
@@ -583,8 +583,8 @@ 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
--
2.24.1
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