[PATCH 5.8 045/118] drm/mediatek: dsi: Fix scrolling of panel with small hfp or hbp

Greg Kroah-Hartman
2020-09-21T16:57:02Z

From: Jitao Shi <jitao.shi@mediatek.com>

[ Upstream commit 35bf948f1edbf507f6e57e0879fa6ea36d2d2930 ]

horizontal_backporch_byte should be hbp * bpp - hbp extra bytes.
So remove the wrong subtraction 10.

Fixes: 7a5bc4e22ecf ("drm/mediatek: change the dsi phytiming calculate method")
Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/mediatek/mtk_dsi.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 02ac55c13a80b..ee011a0633841 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -470,14 +470,13 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
horizontal_sync_active_byte = (vm->hsync_len * dsi_tmp_buf_bpp - 10);

if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
- horizontal_backporch_byte =
- (vm->hback_porch * dsi_tmp_buf_bpp - 10);
+ horizontal_backporch_byte = vm->hback_porch * dsi_tmp_buf_bpp;
else
- horizontal_backporch_byte = ((vm->hback_porch + vm->hsync_len) *
- dsi_tmp_buf_bpp - 10);
+ horizontal_backporch_byte = (vm->hback_porch + vm->hsync_len) *
+ dsi_tmp_buf_bpp;

data_phy_cycles = timing->lpx + timing->da_hs_prepare +
- timing->da_hs_zero + timing->da_hs_exit + 3;
+ timing->da_hs_zero + timing->da_hs_exit;

if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
if ((vm->hfront_porch + vm->hback_porch) * dsi_tmp_buf_bpp >
--
2.25.1