[PATCH 05/20] drm/i915/dp: Handle the RX_CAP_CHANGED HPD IRQ

[Luca Coelho]

On Tue, 2025-07-01 at 13:30 +0300, Imre Deak wrote:
> On Tue, Jul 01, 2025 at 11:03:56AM +0300, Luca Coelho wrote:
> > On Thu, 2025-06-26 at 11:20 +0300, Imre Deak wrote:
> > > From: Imre Deak <imre.deak at gmail.com>
> > > 
> > > Handle the RX_CAP_CHANGED IRQ, which a sink can use to indicate a DPRX
> > > capability change without disconnecting and reconnecting itself (i.e.
> > > through a short vs. long HPD pulse). Handle the IRQ by doing a full
> > > connector detection.
> > > 
> > > Signed-off-by: Imre Deak <imre.deak at gmail.com>
> > > ---
> > >  drivers/gpu/drm/i915/display/intel_dp.c | 8 +++++++-
> > >  1 file changed, 7 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> > > index 453416b9e9bec..c2eadfa060c2d 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > > @@ -5099,7 +5099,7 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp)
> > >  
> > >  		drm_dbg_kms(display->drm, "DPRX ESI: %4ph\n", esi);
> > >  
> > > -		ack[3] |= esi[3] & (LINK_STATUS_CHANGED | DP_TUNNELING_IRQ);
> > > +		ack[3] |= esi[3] & (RX_CAP_CHANGED | LINK_STATUS_CHANGED | DP_TUNNELING_IRQ);
> > >  
> > >  		intel_dp_mst_hpd_irq(intel_dp, esi, ack);
> > >  
> > > @@ -5112,6 +5112,9 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp)
> > >  		if (ack[1] & (DP_DOWN_REP_MSG_RDY | DP_UP_REQ_MSG_RDY))
> > >  			drm_dp_mst_hpd_irq_send_new_request(&intel_dp->mst.mgr);
> > >  
> > > +		if (ack[3] & RX_CAP_CHANGED)
> > > +			reprobe_needed = true;
> > > +
> > >  		if ((ack[3] & LINK_STATUS_CHANGED) || intel_dp->link.force_retrain)
> > >  			intel_dp_check_link_state(intel_dp);
> > >  
> > > @@ -5424,6 +5427,9 @@ static bool intel_dp_check_link_service_irq(struct intel_dp *intel_dp)
> > >  			       DP_LINK_SERVICE_IRQ_VECTOR_ESI0, val) != 1)
> > >  		return false;
> > >  
> > > +	if (val & RX_CAP_CHANGED)
> > > +		reprobe_needed = true;
> > > +
> > >  	if (val & HDMI_LINK_STATUS_CHANGED)
> > >  		intel_dp_handle_hdmi_link_status_change(intel_dp);
> > >  
> > 
> > Same question as to the previous patch.  What happens if the interrupt
> > is not actually handled?
> 
> For the MST case the same thing applies as discussed in the previous
> patch, the acked interrupts will be handled and only those interrupts
> will be acked that are also handled.
> 
> In the SST case here all the interrupts handled were acked above. It's
> possible that an interrupt is acked and then not handled or at least
> indicated that it's handled on purpose (atm the only such case is
> CONNECTED_OFF_ENTRY_REQUESTED), but this will be addressed later in the
> patchset.

Reviewed-by: Luca Coelho <luciano.coelho at intel.com>

--
Cheers,
Luca.