From 9a754f9db1417681a74c022ba4927bfa251156a8 Mon Sep 17 00:00:00 2001 From: Dmitry Baryshkov Date: Mon, 23 Mar 2026 19:36:04 +0800 Subject: [PATCH 1/2] FROMLIST: drm/bridge: display-connector: don't autoenable HPD IRQ If HPD IRQ is enabled in the display_connector's probe, it can be triggered too early, before the DRM connector is completely setup. Use the enable_hpd / disable_hpd callbacks to control enablement of the HPD IRQ. Fixes: 0c275c30176b ("drm/bridge: Add bridge driver for display connectors") Signed-off-by: Dmitry Baryshkov Link: https://lore.kernel.org/all/20260314-dp-connector-hpd-v1-1-786044cedc17@oss.qualcomm.com/ --- drivers/gpu/drm/bridge/display-connector.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/drivers/gpu/drm/bridge/display-connector.c b/drivers/gpu/drm/bridge/display-connector.c index e9f16dbc95353..b2395bb5a7398 100644 --- a/drivers/gpu/drm/bridge/display-connector.c +++ b/drivers/gpu/drm/bridge/display-connector.c @@ -87,6 +87,20 @@ display_connector_bridge_detect(struct drm_bridge *bridge, struct drm_connector return display_connector_detect(bridge); } +static void display_connector_hpd_enable(struct drm_bridge *bridge) +{ + struct display_connector *conn = to_display_connector(bridge); + + enable_irq(conn->hpd_irq); +} + +static void display_connector_hpd_disable(struct drm_bridge *bridge) +{ + struct display_connector *conn = to_display_connector(bridge); + + disable_irq(conn->hpd_irq); +} + static const struct drm_edid *display_connector_edid_read(struct drm_bridge *bridge, struct drm_connector *connector) { @@ -178,6 +192,8 @@ static u32 *display_connector_get_input_bus_fmts(struct drm_bridge *bridge, static const struct drm_bridge_funcs display_connector_bridge_funcs = { .attach = display_connector_attach, .detect = display_connector_bridge_detect, + .hpd_enable = display_connector_hpd_enable, + .hpd_disable = display_connector_hpd_disable, .edid_read = display_connector_edid_read, .atomic_get_output_bus_fmts = display_connector_get_output_bus_fmts, .atomic_get_input_bus_fmts = display_connector_get_input_bus_fmts, @@ -307,6 +323,7 @@ static int display_connector_probe(struct platform_device *pdev) NULL, display_connector_hpd_irq, IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | + IRQF_NO_AUTOEN | IRQF_ONESHOT, "HPD", conn); if (ret) { From 481191bc4a43d3add64d2b1d48c23e3ade19cfc7 Mon Sep 17 00:00:00 2001 From: Dmitry Baryshkov Date: Mon, 23 Mar 2026 19:37:45 +0800 Subject: [PATCH 2/2] FROMLIST: drm/bridge: display-connector: trigger initial HPD event for DP If the DisplayPort drivers use display-connector for the HPD detection, the internal HPD state machine might be not active and thus the hardware might be not able to handle cable detection correctly. Instead it will depend on the externall HPD notifications to set the cable state, bypassing the internal HPD state machine (for example this is the case for the msm DP driver). However if the cable has been plugged before the HPD IRQ has been enabled, there will be no HPD event coming. The drivers might fail detection in such a case. Trigger the HPD notification after enabling the HPD IRQ, propagating the cable insertion state. Fixes: 2e2bf3a5584d ("drm/bridge: display-connector: add DP support") Reported-by: Yongxing Mou Signed-off-by: Dmitry Baryshkov Link: https://lore.kernel.org/all/20260314-dp-connector-hpd-v1-2-786044cedc17@oss.qualcomm.com/ --- drivers/gpu/drm/bridge/display-connector.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/drivers/gpu/drm/bridge/display-connector.c b/drivers/gpu/drm/bridge/display-connector.c index b2395bb5a7398..27866ba158aa5 100644 --- a/drivers/gpu/drm/bridge/display-connector.c +++ b/drivers/gpu/drm/bridge/display-connector.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include @@ -25,6 +26,8 @@ struct display_connector { struct regulator *supply; struct gpio_desc *ddc_en; + + struct work_struct hpd_work; }; static inline struct display_connector * @@ -92,15 +95,29 @@ static void display_connector_hpd_enable(struct drm_bridge *bridge) struct display_connector *conn = to_display_connector(bridge); enable_irq(conn->hpd_irq); + + if (conn->bridge.type == DRM_MODE_CONNECTOR_DisplayPort) + schedule_work(&conn->hpd_work); } static void display_connector_hpd_disable(struct drm_bridge *bridge) { struct display_connector *conn = to_display_connector(bridge); + if (conn->bridge.type == DRM_MODE_CONNECTOR_DisplayPort) + cancel_work_sync(&conn->hpd_work); + disable_irq(conn->hpd_irq); } +static void display_connector_hpd_work(struct work_struct *work) +{ + struct display_connector *conn = container_of(work, struct display_connector, hpd_work); + struct drm_bridge *bridge = &conn->bridge; + + drm_bridge_hpd_notify(bridge, display_connector_detect(bridge)); +} + static const struct drm_edid *display_connector_edid_read(struct drm_bridge *bridge, struct drm_connector *connector) { @@ -395,6 +412,8 @@ static int display_connector_probe(struct platform_device *pdev) conn->bridge.ops |= DRM_BRIDGE_OP_DETECT; if (conn->hpd_irq >= 0) conn->bridge.ops |= DRM_BRIDGE_OP_HPD; + if (conn->hpd_irq >= 0 && type == DRM_MODE_CONNECTOR_DisplayPort) + INIT_WORK(&conn->hpd_work, display_connector_hpd_work); dev_dbg(&pdev->dev, "Found %s display connector '%s' %s DDC bus and %s HPD GPIO (ops 0x%x)\n",