[PATCH v3 2/8] drm/i915/dp: Ensure panel power remains enabled during connector detection

[Imre Deak]

On Wed, Oct 23, 2024 at 06:19:11PM +0300, Jani Nikula wrote:
> On Wed, 16 Oct 2024, Imre Deak <imre.deak at intel.com> wrote:
> > The sink's capabilities, like the DSC caps, depend on the source OUI
> > written to the sink's DPCD registers and so this OUI value should be
> > valid for the whole duration of the detection. An eDP sink will reset
> > this OUI value when the panel power is disabled, so prevent the
> > disabling - happening by default after a 1 sec idle period - for the
> > whole duration of detection.
> >
> > Signed-off-by: Imre Deak <imre.deak at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_dp.c  | 18 +++++++++++++-----
> >  drivers/gpu/drm/i915/display/intel_pps.c | 11 +++++++++++
> >  drivers/gpu/drm/i915/display/intel_pps.h |  1 +
> >  3 files changed, 25 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> > index 977ff2ce18eeb..3da06d25bc4ef 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > @@ -5616,6 +5616,8 @@ intel_dp_detect(struct drm_connector *connector,
> >  
> >  	intel_dp_flush_connector_commits(intel_connector);
> >  
> > +	intel_pps_vdd_on(intel_dp);
> > +
> 
> The comment above this one says, "Must be paired with intel_pps_off()."
> 
> Needs an update.

Ok, missed that. Can change it to "Must be paired with
intel_pps_vdd_off() or - to disable both VDD and panel power -
intel_pps_off()". (The locking requirement stays the same.)

> 
> BR,
> Jani.
> 
> 
> >  	/* Can't disconnect eDP */
> >  	if (intel_dp_is_edp(intel_dp))
> >  		status = edp_detect(intel_dp);
> > @@ -5646,12 +5648,15 @@ intel_dp_detect(struct drm_connector *connector,
> >  
> >  		intel_dp_tunnel_disconnect(intel_dp);
> >  
> > -		goto out;
> > +		goto out_unset_edid;
> >  	}
> >  
> >  	ret = intel_dp_tunnel_detect(intel_dp, ctx);
> > -	if (ret == -EDEADLK)
> > -		return ret;
> > +	if (ret == -EDEADLK) {
> > +		status = ret;
> > +
> > +		goto out_vdd_off;
> > +	}
> >  
> >  	if (ret == 1)
> >  		intel_connector->base.epoch_counter++;
> > @@ -5679,7 +5684,7 @@ intel_dp_detect(struct drm_connector *connector,
> >  		 * with EDID on it
> >  		 */
> >  		status = connector_status_disconnected;
> > -		goto out;
> > +		goto out_unset_edid;
> >  	}
> >  
> >  	/*
> > @@ -5708,7 +5713,7 @@ intel_dp_detect(struct drm_connector *connector,
> >  
> >  	intel_dp_check_device_service_irq(intel_dp);
> >  
> > -out:
> > +out_unset_edid:
> >  	if (status != connector_status_connected && !intel_dp->is_mst)
> >  		intel_dp_unset_edid(intel_dp);
> >  
> > @@ -5717,6 +5722,9 @@ intel_dp_detect(struct drm_connector *connector,
> >  						 status,
> >  						 intel_dp->dpcd,
> >  						 intel_dp->downstream_ports);
> > +out_vdd_off:
> > +	intel_pps_vdd_off(intel_dp);
> > +
> >  	return status;
> >  }
> >  
> > diff --git a/drivers/gpu/drm/i915/display/intel_pps.c b/drivers/gpu/drm/i915/display/intel_pps.c
> > index ffeee9daa5689..64f1f7ea94993 100644
> > --- a/drivers/gpu/drm/i915/display/intel_pps.c
> > +++ b/drivers/gpu/drm/i915/display/intel_pps.c
> > @@ -950,6 +950,17 @@ void intel_pps_vdd_off_unlocked(struct intel_dp *intel_dp, bool sync)
> >  		edp_panel_vdd_schedule_off(intel_dp);
> >  }
> >  
> > +void intel_pps_vdd_off(struct intel_dp *intel_dp)
> > +{
> > +	intel_wakeref_t wakeref;
> > +
> > +	if (!intel_dp_is_edp(intel_dp))
> > +		return;
> > +
> > +	with_intel_pps_lock(intel_dp, wakeref)
> > +		intel_pps_vdd_off_unlocked(intel_dp, false);
> > +}
> > +
> >  void intel_pps_on_unlocked(struct intel_dp *intel_dp)
> >  {
> >  	struct intel_display *display = to_intel_display(intel_dp);
> > diff --git a/drivers/gpu/drm/i915/display/intel_pps.h b/drivers/gpu/drm/i915/display/intel_pps.h
> > index bc5046d536264..c83007152f07d 100644
> > --- a/drivers/gpu/drm/i915/display/intel_pps.h
> > +++ b/drivers/gpu/drm/i915/display/intel_pps.h
> > @@ -34,6 +34,7 @@ void intel_pps_off_unlocked(struct intel_dp *intel_dp);
> >  void intel_pps_check_power_unlocked(struct intel_dp *intel_dp);
> >  
> >  void intel_pps_vdd_on(struct intel_dp *intel_dp);
> > +void intel_pps_vdd_off(struct intel_dp *intel_dp);
> >  void intel_pps_on(struct intel_dp *intel_dp);
> >  void intel_pps_off(struct intel_dp *intel_dp);
> >  void intel_pps_vdd_off_sync(struct intel_dp *intel_dp);
> 
> -- 
> Jani Nikula, Intel