Currently, mtk_dsi_lane_ready (which setup the DSI lane) is triggered
before mtk_dsi_poweron. lanes_ready flag toggle to true during
mtk_dsi_lane_ready function, and the DSI module is set up during
mtk_dsi_poweron.

Later, during panel driver init, mtk_dsi_lane_ready is triggered but does
nothing because lanes are considered ready. Unfortunately, when the panel
driver try to communicate, the DSI returns a timeout.

The solution found here is to put lanes_ready flag to false after the DSI
module setup into mtk_dsi_poweron to init the DSI lanes after the power /
setup of the DSI module.

Signed-off-by: Alexandre Mergnat <amergnat@baylibre.com>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index e036d9394c23..cb546a9e9419 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -643,6 +643,8 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
 	mtk_dsi_config_vdo_timing(dsi);
 	mtk_dsi_set_interrupt_enable(dsi);
 
+	dsi->lanes_ready = false;
+
 	return 0;
 err_disable_engine_clk:
 	clk_disable_unprepare(dsi->engine_clk);

-- 
2.25.1

Hi, Shuijing:

Please help to review this patch.

Regards,
Chun-Kuang.

Alexandre Mergnat <amergnat@baylibre.com> 於 2024年5月23日 週四 下午8:49寫道：
>
> Currently, mtk_dsi_lane_ready (which setup the DSI lane) is triggered
> before mtk_dsi_poweron. lanes_ready flag toggle to true during
> mtk_dsi_lane_ready function, and the DSI module is set up during
> mtk_dsi_poweron.
>
> Later, during panel driver init, mtk_dsi_lane_ready is triggered but does
> nothing because lanes are considered ready. Unfortunately, when the panel
> driver try to communicate, the DSI returns a timeout.
>
> The solution found here is to put lanes_ready flag to false after the DSI
> module setup into mtk_dsi_poweron to init the DSI lanes after the power /
> setup of the DSI module.
>
> Signed-off-by: Alexandre Mergnat <amergnat@baylibre.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index e036d9394c23..cb546a9e9419 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -643,6 +643,8 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
>         mtk_dsi_config_vdo_timing(dsi);
>         mtk_dsi_set_interrupt_enable(dsi);
>
> +       dsi->lanes_ready = false;
> +
>         return 0;
>  err_disable_engine_clk:
>         clk_disable_unprepare(dsi->engine_clk);
>
> --
> 2.25.1
>