From: Roman Vivchar Commit 76255024cadb ("drm/mediatek: mtk_dsi: enable hs clock during pre-enable") moved HS clock enablement from the mtk_output_dsi_enable() to mtk_dsi_poweron(). Later, the commit 3e191eddbdcb ("drm/mediatek: mtk_dsi: Enable HS clock only at pre-enable") moved the call to the mtk_dsi_bridge_atomic_pre_enable(). However, mtk_dsi_lane_ready() explicitly sets mtk_dsi_clk_hs_mode(dsi, 0) so that DSI panels with MIPI_DSI_MODE_LPM can transmit initialization commands in Low-Power mode during their prepare() callback. Enabling the HS clock unconditionally in mtk_dsi_bridge_atomic_pre_enable() overrides this before panel prepare() runs, causing command transmission to fail. Only enable the HS clock in mtk_dsi_bridge_atomic_pre_enable(), when MIPI_DSI_MODE_LPM is not set, and restore mtk_dsi_clk_hs_mode(dsi, 1) in mtk_output_dsi_enable(). This is no-op for non-LPM bridges. Fixes: 76255024cadb ("drm/mediatek: mtk_dsi: enable hs clock during pre-enable") Fixes: 3e191eddbdcb ("drm/mediatek: mtk_dsi: Enable HS clock only at pre-enable") Cc: stable@vger.kernel.org Signed-off-by: Roman Vivchar --- This fix was tested with the Tianma NT36672A panel on the mt6768 platform. --- drivers/gpu/drm/mediatek/mtk_dsi.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c index 7961139333ad..e5b433f353d5 100644 --- a/drivers/gpu/drm/mediatek/mtk_dsi.c +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c @@ -794,6 +794,7 @@ static void mtk_output_dsi_enable(struct mtk_dsi *dsi) return; mtk_dsi_set_mode(dsi); + mtk_dsi_clk_hs_mode(dsi, 1); mtk_dsi_start(dsi); dsi->enabled = true; @@ -858,7 +859,8 @@ static void mtk_dsi_bridge_atomic_pre_enable(struct drm_bridge *bridge, drm_err(drm, "failed to power on dsi\n"); mtk_dsi_lane_ready(dsi); - mtk_dsi_clk_hs_mode(dsi, 1); + if (!(dsi->mode_flags & MIPI_DSI_MODE_LPM)) + mtk_dsi_clk_hs_mode(dsi, 1); } static void mtk_dsi_bridge_atomic_post_disable(struct drm_bridge *bridge, --- base-commit: c03c1a14507dfaf8b856c2608f9ac216021fc222 change-id: 20261019-6768-dsi-fix-9f0c2ca2ba9f Best regards, -- Roman Vivchar