[v3 PATCH] drm/mediatek: dsi: fix scrolling of panel with small hfp or hbp

Jitao Shi
2020-09-17T03:36:00Z

Replace horizontal_backporch_byte with vm->hback_porch * bpp to aovid
flowing judgement negative number.

if ((vm->hfront_porch * dsi_tmp_buf_bpp + horizontal_backporch_byte) >
data_phy_cycles * dsi->lanes + delta)

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
drivers/gpu/drm/mediatek/mtk_dsi.c | 54 ++++++++++++++------------------------
1 file changed, 19 insertions(+), 35 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 16fd99dcdacf..ddddf69ebeaf 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -445,6 +445,7 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
u32 horizontal_backporch_byte;
u32 horizontal_frontporch_byte;
u32 dsi_tmp_buf_bpp, data_phy_cycles;
+ u32 delta;
struct mtk_phy_timing *timing = &dsi->phy_timing;

struct videomode *vm = &dsi->vm;
@@ -475,42 +476,25 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
data_phy_cycles = timing->lpx + timing->da_hs_prepare +
timing->da_hs_zero + timing->da_hs_exit + 3;

- if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
- if ((vm->hfront_porch + vm->hback_porch) * dsi_tmp_buf_bpp >
- data_phy_cycles * dsi->lanes + 18) {
- horizontal_frontporch_byte =
- vm->hfront_porch * dsi_tmp_buf_bpp -
- (data_phy_cycles * dsi->lanes + 18) *
- vm->hfront_porch /
- (vm->hfront_porch + vm->hback_porch);
-
- horizontal_backporch_byte =
- horizontal_backporch_byte -
- (data_phy_cycles * dsi->lanes + 18) *
- vm->hback_porch /
- (vm->hfront_porch + vm->hback_porch);
- } else {
- DRM_WARN("HFP less than d-phy, FPS will under 60Hz\n");
- horizontal_frontporch_byte = vm->hfront_porch *
- dsi_tmp_buf_bpp;
- }
+ delta = (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) ? 18 : 12;
+
+ if ((vm->hfront_porch * dsi_tmp_buf_bpp + horizontal_backporch_byte) >
+ data_phy_cycles * dsi->lanes + delta) {
+ horizontal_frontporch_byte =
+ vm->hfront_porch * dsi_tmp_buf_bpp -
+ (data_phy_cycles * dsi->lanes + delta) *
+ vm->hfront_porch /
+ (vm->hfront_porch + vm->hback_porch);
+
+ horizontal_backporch_byte =
+ horizontal_backporch_byte -
+ (data_phy_cycles * dsi->lanes + delta) *
+ vm->hback_porch /
+ (vm->hfront_porch + vm->hback_porch);
} else {
- if ((vm->hfront_porch + vm->hback_porch) * dsi_tmp_buf_bpp >
- data_phy_cycles * dsi->lanes + 12) {
- horizontal_frontporch_byte =
- vm->hfront_porch * dsi_tmp_buf_bpp -
- (data_phy_cycles * dsi->lanes + 12) *
- vm->hfront_porch /
- (vm->hfront_porch + vm->hback_porch);
- horizontal_backporch_byte = horizontal_backporch_byte -
- (data_phy_cycles * dsi->lanes + 12) *
- vm->hback_porch /
- (vm->hfront_porch + vm->hback_porch);
- } else {
- DRM_WARN("HFP less than d-phy, FPS will under 60Hz\n");
- horizontal_frontporch_byte = vm->hfront_porch *
- dsi_tmp_buf_bpp;
- }
+ DRM_WARN("HFP + HBP less than d-phy, FPS will under 60Hz\n");
+ horizontal_frontporch_byte = vm->hfront_porch *
+ dsi_tmp_buf_bpp;
}

writel(horizontal_sync_active_byte, dsi->regs + DSI_HSA_WC);
--
2.12.5