[PATCH 1/6] drm/connector: report IRQ_HPD events to drm_connector_oob_hotplug_event()

Dmitry Baryshkov
2026-04-15T23:22:42Z

The DisplayPort standard defines a special kind of events called IRQ.
These events are used to notify DP Source about the events on the Sink
side. It is extremely important for DP MST handling, where the MST
events are reported through this IRQ.

In case of the USB-C DP AltMode there is no actual HPD pulse, but the
events are ported through the bits in the AltMode VDOs.

Extend the drm_connector_oob_hotplug_event() interface and report IRQ
events to the DisplayPort Sink drivers.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
drivers/gpu/drm/drm_connector.c | 4 +++-
drivers/usb/typec/altmodes/displayport.c | 12 ++++++++----
include/drm/drm_connector.h | 3 ++-
3 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 47dc53c4a738..5fdacbd84bd7 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -3510,6 +3510,7 @@ struct drm_connector *drm_connector_find_by_fwnode(struct fwnode_handle *fwnode)
* drm_connector_oob_hotplug_event - Report out-of-band hotplug event to connector
* @connector_fwnode: fwnode_handle to report the event on
* @status: hot plug detect logical state
+ * @irq_hpd: HPD pulse detected
*
* On some hardware a hotplug event notification may come from outside the display
* driver / device. An example of this is some USB Type-C setups where the hardware
@@ -3520,7 +3521,8 @@ struct drm_connector *drm_connector_find_by_fwnode(struct fwnode_handle *fwnode)
* a drm_connector reference through calling drm_connector_find_by_fwnode().
*/
void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode,
- enum drm_connector_status status)
+ enum drm_connector_status status,
+ bool irq_hpd)
{
struct drm_connector *connector;

diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
index 35d9c3086990..0cade62da905 100644
--- a/drivers/usb/typec/altmodes/displayport.c
+++ b/drivers/usb/typec/altmodes/displayport.c
@@ -189,7 +189,8 @@ static int dp_altmode_status_update(struct dp_altmode *dp)
} else {
drm_connector_oob_hotplug_event(dp->connector_fwnode,
hpd ? connector_status_connected :
- connector_status_disconnected);
+ connector_status_disconnected,
+ hpd && irq_hpd);
dp->hpd = hpd;
sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
if (hpd && irq_hpd) {
@@ -212,7 +213,8 @@ static int dp_altmode_configured(struct dp_altmode *dp)
*/
if (dp->pending_hpd) {
drm_connector_oob_hotplug_event(dp->connector_fwnode,
- connector_status_connected);
+ connector_status_connected,
+ dp->pending_irq_hpd);
sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
dp->pending_hpd = false;
if (dp->pending_irq_hpd) {
@@ -397,7 +399,8 @@ static int dp_altmode_vdm(struct typec_altmode *alt,
dp->data.conf = 0;
if (dp->hpd) {
drm_connector_oob_hotplug_event(dp->connector_fwnode,
- connector_status_disconnected);
+ connector_status_disconnected,
+ false);
dp->hpd = false;
sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
}
@@ -827,7 +830,8 @@ void dp_altmode_remove(struct typec_altmode *alt)

if (dp->connector_fwnode) {
drm_connector_oob_hotplug_event(dp->connector_fwnode,
- connector_status_disconnected);
+ connector_status_disconnected,
+ false);

fwnode_handle_put(dp->connector_fwnode);
}
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index f83f28cae207..e8e7e6c9eb5c 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -2521,7 +2521,8 @@ drm_connector_is_unregistered(struct drm_connector *connector)
}

void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode,
- enum drm_connector_status status);
+ enum drm_connector_status status,
+ bool irq_hpd);
const char *drm_get_connector_type_name(unsigned int connector_type);
const char *drm_get_connector_status_name(enum drm_connector_status status);
const char *drm_get_subpixel_order_name(enum subpixel_order order);

--
2.47.3