drm/mediatek: reduce the hbp and hfp for phy timing
diff mbox series

Message ID 20191213095215.17068-1-jitao.shi@mediatek.com
State New
Headers show
Series
  • drm/mediatek: reduce the hbp and hfp for phy timing
Related show

Commit Message

Jitao Shi Dec. 13, 2019, 9:52 a.m. UTC
There are some extra data transfer in dsi.
ex. LPX, hs_prepare, hs_zero, hs_exit and the sof/eof of dsi packet.
This signal will enlarge the line time. So the real frame on dsi bus
will be lower than calc by video timing.

So dsi driver reduces the hbp and hfp to keep the line time.

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 67 +++++++++++++++++-------------
 1 file changed, 38 insertions(+), 29 deletions(-)

Comments

Hsin-Yi Wang Dec. 16, 2019, 2:42 a.m. UTC | #1
On Fri, Dec 13, 2019 at 9:52 AM Jitao Shi <jitao.shi@mediatek.com> wrote:
>
> There are some extra data transfer in dsi.
> ex. LPX, hs_prepare, hs_zero, hs_exit and the sof/eof of dsi packet.
> This signal will enlarge the line time. So the real frame on dsi bus
> will be lower than calc by video timing.
>
> So dsi driver reduces the hbp and hfp to keep the line time.
>
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
Tested-by: Hsin-Yi Wang <hsinyi@chromium.org>
> ---

Tested on mt8183 and mt8173
Enric Balletbo Serra Dec. 16, 2019, 10:30 a.m. UTC | #2
Hi all,

Missatge de Hsin-Yi Wang <hsinyi@chromium.org> del dia dl., 16 de des.
2019 a les 3:42:
>
> On Fri, Dec 13, 2019 at 9:52 AM Jitao Shi <jitao.shi@mediatek.com> wrote:
> >
> > There are some extra data transfer in dsi.
> > ex. LPX, hs_prepare, hs_zero, hs_exit and the sof/eof of dsi packet.
> > This signal will enlarge the line time. So the real frame on dsi bus
> > will be lower than calc by video timing.
> >
> > So dsi driver reduces the hbp and hfp to keep the line time.
> >

This patch not only reduces the hbp and hfp for phy timing, it also
fixes an actual issue for MT8173 boards (i.e. Acer Chromebook R 13)
which is that the display is not working anymore (black screen) after
7a5bc4e22ecfd74dc3662342beaa909770a3b786 "drm/mediatek: change the dsi
phytiming calculate method". So the patch is probably missing a:

Fixes: 7a5bc4e22ecf ("drm/mediatek: change the dsi phytiming calculate method")

And would be nice to have this patch applied for 5.5

> > Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> Tested-by: Hsin-Yi Wang <hsinyi@chromium.org>

If it helps, you can also add my

Tested-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

Thanks,
 Enric

> > ---
>
> Tested on mt8183 and mt8173
>
> _______________________________________________
> Linux-mediatek mailing list
> Linux-mediatek@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-mediatek
CK Hu Dec. 17, 2019, 2:36 a.m. UTC | #3
Hi,

On Mon, 2019-12-16 at 11:30 +0100, Enric Balletbo Serra wrote:
> Hi all,
> 
> Missatge de Hsin-Yi Wang <hsinyi@chromium.org> del dia dl., 16 de des.
> 2019 a les 3:42:
> >
> > On Fri, Dec 13, 2019 at 9:52 AM Jitao Shi <jitao.shi@mediatek.com> wrote:
> > >
> > > There are some extra data transfer in dsi.
> > > ex. LPX, hs_prepare, hs_zero, hs_exit and the sof/eof of dsi packet.
> > > This signal will enlarge the line time. So the real frame on dsi bus
> > > will be lower than calc by video timing.
> > >
> > > So dsi driver reduces the hbp and hfp to keep the line time.
> > >
> 
> This patch not only reduces the hbp and hfp for phy timing, it also
> fixes an actual issue for MT8173 boards (i.e. Acer Chromebook R 13)
> which is that the display is not working anymore (black screen) after
> 7a5bc4e22ecfd74dc3662342beaa909770a3b786 "drm/mediatek: change the dsi
> phytiming calculate method". So the patch is probably missing a:
> 
> Fixes: 7a5bc4e22ecf ("drm/mediatek: change the dsi phytiming calculate method")
> 
> And would be nice to have this patch applied for 5.5
> 
> > > Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> > Tested-by: Hsin-Yi Wang <hsinyi@chromium.org>
> 
> If it helps, you can also add my
> 
> Tested-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> 
> Thanks,
>  Enric

Applied to mediatek-drm-fixes-5.5 [1], thank you all.

[1]
https://github.com/ckhu-mediatek/linux.git-tags/commits/mediatek-drm-fixes-5.5

Regards,
CK

> 
> > > ---
> >
> > Tested on mt8183 and mt8173
> >
> > _______________________________________________
> > Linux-mediatek mailing list
> > Linux-mediatek@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-mediatek

Patch
diff mbox series

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index e9931bbbe846..f247fad47709 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -230,28 +230,25 @@  static void mtk_dsi_mask(struct mtk_dsi *dsi, u32 offset, u32 mask, u32 data)
 static void mtk_dsi_phy_timconfig(struct mtk_dsi *dsi)
 {
 	u32 timcon0, timcon1, timcon2, timcon3;
-	u32 ui, cycle_time;
+	u32 data_rate_mhz = DIV_ROUND_UP(dsi->data_rate, 1000000);
 	struct mtk_phy_timing *timing = &dsi->phy_timing;
 
-	ui = DIV_ROUND_UP(1000000000, dsi->data_rate);
-	cycle_time = div_u64(8000000000ULL, dsi->data_rate);
+	timing->lpx = (60 * data_rate_mhz / (8 * 1000)) + 1;
+	timing->da_hs_prepare = (80 * data_rate_mhz + 4 * 1000) / 8000;
+	timing->da_hs_zero = (170 * data_rate_mhz + 10 * 1000) / 8000 + 1 -
+				 timing->da_hs_prepare;
+	timing->da_hs_trail = timing->da_hs_prepare + 1;
 
-	timing->lpx = NS_TO_CYCLE(60, cycle_time);
-	timing->da_hs_prepare = NS_TO_CYCLE(50 + 5 * ui, cycle_time);
-	timing->da_hs_zero = NS_TO_CYCLE(110 + 6 * ui, cycle_time);
-	timing->da_hs_trail = NS_TO_CYCLE(77 + 4 * ui, cycle_time);
+	timing->ta_go = 4 * timing->lpx - 2;
+	timing->ta_sure = timing->lpx + 2;
+	timing->ta_get = 4 * timing->lpx;
+	timing->da_hs_exit = 2 * timing->lpx + 1;
 
-	timing->ta_go = 4 * timing->lpx;
-	timing->ta_sure = 3 * timing->lpx / 2;
-	timing->ta_get = 5 * timing->lpx;
-	timing->da_hs_exit = 2 * timing->lpx;
-
-	timing->clk_hs_zero = NS_TO_CYCLE(336, cycle_time);
-	timing->clk_hs_trail = NS_TO_CYCLE(100, cycle_time) + 10;
-
-	timing->clk_hs_prepare = NS_TO_CYCLE(64, cycle_time);
-	timing->clk_hs_post = NS_TO_CYCLE(80 + 52 * ui, cycle_time);
-	timing->clk_hs_exit = 2 * timing->lpx;
+	timing->clk_hs_prepare = 70 * data_rate_mhz / (8 * 1000);
+	timing->clk_hs_post = timing->clk_hs_prepare + 8;
+	timing->clk_hs_trail = timing->clk_hs_prepare;
+	timing->clk_hs_zero = timing->clk_hs_trail * 4;
+	timing->clk_hs_exit = 2 * timing->clk_hs_trail;
 
 	timcon0 = timing->lpx | timing->da_hs_prepare << 8 |
 		  timing->da_hs_zero << 16 | timing->da_hs_trail << 24;
@@ -482,27 +479,39 @@  static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
 			dsi_tmp_buf_bpp - 10);
 
 	data_phy_cycles = timing->lpx + timing->da_hs_prepare +
-				  timing->da_hs_zero + timing->da_hs_exit + 2;
+				  timing->da_hs_zero + timing->da_hs_exit + 3;
 
 	if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
-		if (vm->hfront_porch * dsi_tmp_buf_bpp >
+		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;
+			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;
 		}
 	} else {
-		if (vm->hfront_porch * dsi_tmp_buf_bpp >
+		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;
+			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 *