Re: [PATCH v4 1/8] drm/connector: report out-of-band IRQ_HPD events

[Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>]

On Tue, Jun 09, 2026 at 03:20:01PM +0200, Maxime Ripard wrote:
> Hi,
> 
> On Mon, Jun 08, 2026 at 12:33:02AM +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 reported through the bits in the AltMode VDOs.
> > 
> > Rename drm_connector_oob_hotplug_event() to drm_connector_dp_oob_status()
> > and extend its interface to report IRQ events to the DisplayPort Sink
> > drivers.
> > 
> > Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> > ---
> >  drivers/gpu/drm/drm_connector.c          | 20 ++++++++++++--------
> >  drivers/usb/typec/altmodes/displayport.c | 23 +++++++++++++++--------
> >  include/drm/drm_connector.h              | 21 +++++++++++++++++++--
> >  3 files changed, 46 insertions(+), 18 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> > index 3fa4d2082cd7..bb128dd0263a 100644
> > --- a/drivers/gpu/drm/drm_connector.c
> > +++ b/drivers/gpu/drm/drm_connector.c
> > @@ -3502,20 +3502,24 @@ 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
> > + * drm_connector_dp_oob_status - Report out-of-band hotplug event to DisplayPort 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
> > - * muxes the DisplayPort data and aux-lines but does not pass the altmode HPD
> > - * status bit to the GPU's DP HPD pin.
> > + * In some cases when DisplayPort signals are being routed through the USB
> > + * Type-C port the hotplug event notifications come from outside of the display
> > + * driver / device. In this case hardware muxes the DisplayPort data and
> > + * AUX-lines but does not pass the altmode HPD status bit to the GPU's DP HPD
> > + * pin.
> >   *
> >   * This function can be used to report these out-of-band events after obtaining
> >   * 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)
> > +void drm_connector_dp_oob_status(struct fwnode_handle *connector_fwnode,
> > +				 enum drm_connector_status status,
> > +				 enum drm_connector_status_extra extra_status)
> 
> Thanks for the renaming, but I think we can also rename
> drm_connector_status_extra to something a bit more descriptive now?
> drm_connector_dp_oob_event? status?

I did not want to introduce a DP-specific interface, keeping the HDMI
eARC HPD in mind. But... Let's get it nice for DP first and handle eARC
if the need arives.

-- 
With best wishes
Dmitry

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