[Intel-gfx] [PATCH v2 4/9] drm/i915/psr: Begin to handle PSR/PSR2 errors set by sink

[Dhinakaran Pandiyan]

On Wed, 2018-04-18 at 15:43 -0700, José Roberto de Souza wrote:
> eDP spec states that sink device will do a short pulse in HPD
> line when there is a PSR/PSR2 error that needs to be handled by
> source, this is handling the first and most simples error:
> DP_PSR_SINK_INTERNAL_ERROR.
> 
> Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> ---
> 
> Changes from v1:
> - printing a debug message when sink assert a error
> 
>  drivers/gpu/drm/i915/intel_dp.c  |  2 ++
>  drivers/gpu/drm/i915/intel_drv.h |  1 +
>  drivers/gpu/drm/i915/intel_psr.c | 48 +++++++++++++++++++++++++++++---
>  3 files changed, 47 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 62f82c4298ac..701963a192ee 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -4462,6 +4462,8 @@ intel_dp_short_pulse(struct intel_dp *intel_dp)
>  	if (intel_dp_needs_link_retrain(intel_dp))
>  		return false;
>  
> +	intel_psr_hpd_short_pulse_handle(intel_dp);
	 intel_psr_short_pulse() should be sufficient.

> +
>  	if (intel_dp->compliance.test_type == DP_TEST_LINK_TRAINING) {
>  		DRM_DEBUG_KMS("Link Training Compliance Test requested\n");
>  		/* Send a Hotplug Uevent to userspace to start modeset */
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 5bd2263407b2..b79e15ecd052 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1901,6 +1901,7 @@ void intel_psr_single_frame_update(struct drm_i915_private *dev_priv,
>  				   unsigned frontbuffer_bits);
>  void intel_psr_compute_config(struct intel_dp *intel_dp,
>  			      struct intel_crtc_state *crtc_state);
> +void intel_psr_hpd_short_pulse_handle(struct intel_dp *intel_dp);
>  
>  /* intel_runtime_pm.c */
>  int intel_power_domains_init(struct drm_i915_private *);
> diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
> index 934498505356..4cb27faab707 100644
> --- a/drivers/gpu/drm/i915/intel_psr.c
> +++ b/drivers/gpu/drm/i915/intel_psr.c
> @@ -996,6 +996,15 @@ void intel_psr_invalidate(struct drm_i915_private *dev_priv,
>  	mutex_unlock(&dev_priv->psr.lock);
>  }
>  
> +static void intel_psr_schedule_activate_work(struct drm_i915_private *dev_priv)
> +{
> +	if (dev_priv->psr.active || dev_priv->psr.busy_frontbuffer_bits
> +	    || work_busy(&dev_priv->psr.work.work))
> +		return;
> +
> +	schedule_delayed_work(&dev_priv->psr.work, msecs_to_jiffies(100));
> +}
> +
>  /**
>   * intel_psr_flush - Flush PSR
>   * @dev_priv: i915 device
> @@ -1052,10 +1061,8 @@ void intel_psr_flush(struct drm_i915_private *dev_priv,
>  		}
>  	}
>  
> -	if (!dev_priv->psr.active && !dev_priv->psr.busy_frontbuffer_bits)
> -		if (!work_busy(&dev_priv->psr.work.work))
> -			schedule_delayed_work(&dev_priv->psr.work,
> -					      msecs_to_jiffies(100));
> +	intel_psr_schedule_activate_work(dev_priv);
> +
>  	mutex_unlock(&dev_priv->psr.lock);
>  }
>  
> @@ -1122,3 +1129,36 @@ void intel_psr_init(struct drm_i915_private *dev_priv)
>  		dev_priv->psr.exit = hsw_psr_exit;
>  	}
>  }
> +
> +void intel_psr_hpd_short_pulse_handle(struct intel_dp *intel_dp)
> +{
> +	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
> +	struct drm_device *dev = intel_dig_port->base.base.dev;
> +	struct drm_i915_private *dev_priv = to_i915(dev);
> +	struct i915_psr *psr = &dev_priv->psr;
> +	uint8_t val;
> +
> +	if (!HAS_PSR(dev_priv) || !intel_dp_is_edp(intel_dp))
> +		return;
> +
> +	mutex_lock(&psr->lock);
> +
> +	if (psr->enabled != intel_dp)
> +		goto not_enabled;
> +
> +	if (drm_dp_dpcd_readb(&intel_dp->aux, DP_PSR_STATUS, &val) != 1) {
> +		DRM_DEBUG_KMS("PSR_STATUS read failed\n");

Since we can't handle the irq without reading the dpcd and the irq is
potentially an error condition, I think this should be DRM_ERROR.


> +		goto dpcd_error;
> +	}
> +
> +	if ((val & DP_PSR_SINK_STATE_MASK) == DP_PSR_SINK_INTERNAL_ERROR) {
> +		DRM_DEBUG_KMS("PSR sink internal error, exiting PSR\n");
> +		intel_psr_exit(dev_priv);

Shouldn't this be disabling PSR? Exit will allow for re-activation
immediately. An unknown error in the sink IMO should disable PSR for
good.

> +	}
> +
> +	/* TODO: handle other PSR/PSR2 errors */
> +dpcd_error:
> +	intel_psr_schedule_activate_work(dev_priv);

Why? There is no intel_psr_exit() before the goto.


> +not_enabled:
> +	mutex_unlock(&psr->lock);
> +}