[PATCH v2 13/18] drm/mediatek: dsi: Improves the DSI lane setup robustness

From: Alexandre Mergnat
Date: Tue Apr 16 2024 - 11:58:12 EST


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@xxxxxxxxxxxx>
---
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 9501f4019199..b3f33d4d3d5c 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -642,6 +642,8 @@ 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