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

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, Oct 16, 2024 at 04:23:59PM +0300, Imre Deak 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@intel.com>

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.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);
> +
>  	/* 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);
> -- 
> 2.44.2

-- 
Ville Syrjälä
Intel