2023-01-10 05:57:56

by Xinlei Lee (李昕磊)

Subject: [PATCH v2 1/3] drm/mediatek: dsi: Reduce the time of dsi from LP11 to sending cmd

From: Xinlei Lee <[email protected]>

According to Figure 16 Turnaround Procedure on page 36 in [1], you
can see the status of LP-00 -> LP10 -> LP11. This state can correspond
to the state of DSI from LP00 -> LP11 in mtk_dsi_lane_ready function
in mtk_dsi.c.

LP-00 -> LP10 -> LP11 takes about 2*TLPX time (refer to [1] page 51
to see that TLPX is 50ns)

The delay at the end of the mtk_dsi_lane_ready function should be
greater than the 2*TLPX specified by the DSI spec, and less than
the time specified by the DSI_RX (generally 6ms to 40ms), to avoid
problems caused by the RX specification

[1]:mipi_D-PHY_specification_v1-1

Fixes: 39e8d062b03c ("drm/mediatek: Keep dsi as LP00 before dcs cmds transfer")
Signed-off-by: Xinlei Lee <[email protected]>
Acked-by: Sam Ravnborg <[email protected]>
Reviewed-by: AngeloGioacchino Del Regno <[email protected]>
---
drivers/gpu/drm/mediatek/mtk_dsi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 3b7d13028fb6..9e1363c9fcdb 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -721,7 +721,7 @@ static void mtk_dsi_lane_ready(struct mtk_dsi *dsi)
mtk_dsi_clk_ulp_mode_leave(dsi);
mtk_dsi_lane0_ulp_mode_leave(dsi);
mtk_dsi_clk_hs_mode(dsi, 0);
- msleep(20);
+ usleep_range(1000, 3000);
/* The reaction time after pulling up the mipi signal for dsi_rx */
}
}
--
2.18.0

2023-01-27 00:14:18

by Chun-Kuang Hu

Subject: Re: [PATCH v2 1/3] drm/mediatek: dsi: Reduce the time of dsi from LP11 to sending cmd

Hi, Xinlei:

<[email protected]> 於 2023年1月10日 週二 下午1:55寫道：
>
> From: Xinlei Lee <[email protected]>
>
> According to Figure 16 Turnaround Procedure on page 36 in [1], you
> can see the status of LP-00 -> LP10 -> LP11. This state can correspond
> to the state of DSI from LP00 -> LP11 in mtk_dsi_lane_ready function
> in mtk_dsi.c.
>
> LP-00 -> LP10 -> LP11 takes about 2*TLPX time (refer to [1] page 51
> to see that TLPX is 50ns)
>
> The delay at the end of the mtk_dsi_lane_ready function should be
> greater than the 2*TLPX specified by the DSI spec, and less than
> the time specified by the DSI_RX (generally 6ms to 40ms), to avoid
> problems caused by the RX specification

Applied to mediatek-drm-next [1], thanks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-next

Regards,
Chun-Kuang.

>
> [1]:mipi_D-PHY_specification_v1-1
>
> Fixes: 39e8d062b03c ("drm/mediatek: Keep dsi as LP00 before dcs cmds transfer")
> Signed-off-by: Xinlei Lee <[email protected]>
> Acked-by: Sam Ravnborg <[email protected]>
> Reviewed-by: AngeloGioacchino Del Regno <[email protected]>
> ---
> drivers/gpu/drm/mediatek/mtk_dsi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 3b7d13028fb6..9e1363c9fcdb 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -721,7 +721,7 @@ static void mtk_dsi_lane_ready(struct mtk_dsi *dsi)
> mtk_dsi_clk_ulp_mode_leave(dsi);
> mtk_dsi_lane0_ulp_mode_leave(dsi);
> mtk_dsi_clk_hs_mode(dsi, 0);
> - msleep(20);
> + usleep_range(1000, 3000);
> /* The reaction time after pulling up the mipi signal for dsi_rx */
> }
> }
> --
> 2.18.0
>