Re: [PATCH RESEND v3 1/6] drm/connector: report IRQ_HPD events to drm_connector_oob_hotplug_event()

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Wed, May 13, 2026 at 09:23:21PM +0300, Dmitry Baryshkov wrote:
> 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>

The displayport altmode looks okay to me. FWIW:

Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
>  drivers/gpu/drm/drm_connector.c          |  5 ++++-
>  drivers/usb/typec/altmodes/displayport.c | 15 +++++++++++----
>  include/drm/drm_connector.h              | 19 ++++++++++++++++++-
>  3 files changed, 33 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index 47dc53c4a738..edee9daccd51 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -3510,6 +3510,8 @@ 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
> + * @extra_status: additional information provided by the sink without changing
> + * the HPD state (or in addition to such a change).
>   *
>   * 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 +3522,8 @@ 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,
> +				     enum drm_connector_status_extra extra_status)
>  {
>  	struct drm_connector *connector;
>  
> diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
> index 35d9c3086990..7182a8e2e710 100644
> --- a/drivers/usb/typec/altmodes/displayport.c
> +++ b/drivers/usb/typec/altmodes/displayport.c
> @@ -189,7 +189,9 @@ 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) ? DRM_CONNECTOR_DP_IRQ_HPD :
> +								   DRM_CONNECTOR_NO_EXTRA_STATUS);
>  		dp->hpd = hpd;
>  		sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
>  		if (hpd && irq_hpd) {
> @@ -212,7 +214,10 @@ 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 ?
> +						DRM_CONNECTOR_DP_IRQ_HPD :
> +						DRM_CONNECTOR_NO_EXTRA_STATUS);
>  		sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
>  		dp->pending_hpd = false;
>  		if (dp->pending_irq_hpd) {
> @@ -397,7 +402,8 @@ 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,
> +								DRM_CONNECTOR_NO_EXTRA_STATUS);
>  				dp->hpd = false;
>  				sysfs_notify(&dp->alt->dev.kobj, "displayport", "hpd");
>  			}
> @@ -827,7 +833,8 @@ 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,
> +						DRM_CONNECTOR_NO_EXTRA_STATUS);
>  
>  		fwnode_handle_put(dp->connector_fwnode);
>  	}
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index f83f28cae207..e05197e970d3 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -91,6 +91,22 @@ enum drm_connector_status {
>  	connector_status_unknown = 3,
>  };
>  
> +/**
> + * enum drm_connector_status_extra - additional events sent by the sink /
> + * display together or in replacement of the HPD status changes.
> + */
> +enum drm_connector_status_extra {
> +	/**
> +	 * @DRM_CONNECTOR_NO_EXTRA_STATUS: No additional status reported.
> +	 */
> +	DRM_CONNECTOR_NO_EXTRA_STATUS,
> +	/**
> +	 * @DRM_CONNECTOR_DP_IRQ_HPD: DisplayPort Sink has sent the
> +	 * IRQ_HPD (either by the HPD short pulse or via the AltMode event).
> +	 */
> +	DRM_CONNECTOR_DP_IRQ_HPD,
> +};
> +
>  /**
>   * enum drm_connector_registration_state - userspace registration status for
>   * a &drm_connector
> @@ -2521,7 +2537,8 @@ 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,
> +				     enum drm_connector_status_extra extra_status);
>  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

-- 
heikki