On Fri, 2014-08-22 at 17:21 +0300, ville.syrjala@linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> The power sequencer loses its state when the disp2d power well is down.
> Clear the dev_priv->pps_pipe tracking so that the power sequencer state
> gets reinitialized the next time it's needed.
> 
> v2: Fix the pps_mutex vs. power_domain mutex deadlock by taking power
>     domain reference first
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
> Imre noticed my previouys attempt was utter garbage. Let's try again. Again maybe
> we want to squash with 10/14 or at least move the edp_pps_{lock,unlock}() introduction
> there to avoid churn.
> 
> The alternative of trying to plumb all the power domain calls out from under
> pps_mutex seemed a bit too nasty to me, so I opted for this approach instead.
> 
>  drivers/gpu/drm/i915/intel_dp.c  | 157 +++++++++++++++++++++++++--------------
>  drivers/gpu/drm/i915/intel_drv.h |   1 +
>  drivers/gpu/drm/i915/intel_pm.c  |   2 +
>  3 files changed, 106 insertions(+), 54 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index d6fe1a2..3468315 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -389,6 +389,67 @@ vlv_initial_power_sequencer_setup(struct intel_dp *intel_dp)
>  						      &power_seq);
>  }
>  
> +void vlv_power_sequencer_reset(struct drm_i915_private *dev_priv)
> +{
> +	struct drm_device *dev = dev_priv->dev;
> +	struct intel_encoder *encoder;
> +
> +	if (WARN_ON(!IS_VALLEYVIEW(dev)))
> +		return;
> +
> +	/*
> +	 * We can't grab pps_mutex here due to deadlock with power_domain
> +	 * mutex when power_domain functions are called while holding pps_mutex.
> +	 * That also means that in order to use pps_pipe the code needs to
> +	 * hold both a power domain reference and pps_mutex, and the power domain
> +	 * reference get/put must be done while _not_ holding pps_mutex.
> +	 * edp_pps_{lock,unlock}() do these steps in the correct order, so one
> +	 * should use them always.
> +	 */
> +
> +	list_for_each_entry(encoder, &dev->mode_config.encoder_list, base.head) {
> +		struct intel_dp *intel_dp;
> +
> +		if (encoder->type != INTEL_OUTPUT_EDP)
> +			continue;
> +
> +		intel_dp = enc_to_intel_dp(&encoder->base);
> +		intel_dp->pps_pipe = INVALID_PIPE;
> +	}
> +}
> +
> +static void edp_pps_lock(struct intel_dp *intel_dp)
> +{
> +	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
> +	struct intel_encoder *encoder = &intel_dig_port->base;
> +	struct drm_device *dev = encoder->base.dev;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	enum intel_display_power_domain power_domain;
> +
> +	/*
> +	 * See vlv_power_sequencer_reset() why we need
> +	 * a power domain reference here.
> +	 */
> +	power_domain = intel_display_port_power_domain(encoder);
> +	intel_display_power_get(dev_priv, power_domain);
> +
> +	mutex_lock(&dev_priv->pps_mutex);
> +}
> +
> +static void edp_pps_unlock(struct intel_dp *intel_dp)
> +{
> +	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
> +	struct intel_encoder *encoder = &intel_dig_port->base;
> +	struct drm_device *dev = encoder->base.dev;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	enum intel_display_power_domain power_domain;
> +
> +	mutex_unlock(&dev_priv->pps_mutex);
> +
> +	power_domain = intel_display_port_power_domain(encoder);
> +	intel_display_power_put(dev_priv, power_domain);
> +}
> +
>  static u32 _pp_ctrl_reg(struct intel_dp *intel_dp)
>  {
>  	struct drm_device *dev = intel_dp_to_dev(intel_dp);
> @@ -425,7 +486,7 @@ static int edp_notify_handler(struct notifier_block *this, unsigned long code,
>  	if (!IS_VALLEYVIEW(dev) || !is_edp(intel_dp) || code != SYS_RESTART)
>  		return 0;
>  
> -	mutex_lock(&dev_priv->pps_mutex);
> +	edp_pps_lock(intel_dp);
>  
>  	pipe = vlv_power_sequencer_pipe(intel_dp);
>  
> @@ -439,7 +500,7 @@ static int edp_notify_handler(struct notifier_block *this, unsigned long code,
>  	I915_WRITE(pp_ctrl_reg, PANEL_UNLOCK_REGS | PANEL_POWER_OFF);
>  	msleep(intel_dp->panel_power_cycle_delay);
>  
> -	mutex_unlock(&dev_priv->pps_mutex);
> +	edp_pps_unlock(intel_dp);
>  
>  	return 0;
>  }
> @@ -458,17 +519,13 @@ static bool edp_have_panel_vdd(struct intel_dp *intel_dp)
>  {
>  	struct drm_device *dev = intel_dp_to_dev(intel_dp);
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> -	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
> -	struct intel_encoder *intel_encoder = &intel_dig_port->base;
> -	enum intel_display_power_domain power_domain;
>  
>  	lockdep_assert_held(&dev_priv->pps_mutex);
>  
> -	power_domain = intel_display_port_power_domain(intel_encoder);
> -	return intel_display_power_enabled(dev_priv, power_domain) &&
> -	       (I915_READ(_pp_ctrl_reg(intel_dp)) & EDP_FORCE_VDD) != 0;
> +	return I915_READ(_pp_ctrl_reg(intel_dp)) & EDP_FORCE_VDD;
>  }
>  
> +

Redundant w/s change.

>  static void
>  intel_dp_check_edp(struct intel_dp *intel_dp)
>  {
> @@ -614,7 +671,7 @@ intel_dp_aux_ch(struct intel_dp *intel_dp,
>  	bool has_aux_irq = HAS_AUX_IRQ(dev);
>  	bool vdd;
>  
> -	mutex_lock(&dev_priv->pps_mutex);
> +	edp_pps_lock(intel_dp);
>  
>  	/*
>  	 * We will be called with VDD already enabled for dpcd/edid/oui reads.
> @@ -731,7 +788,7 @@ out:
>  	if (vdd)
>  		edp_panel_vdd_off(intel_dp, false);
>  
> -	mutex_unlock(&dev_priv->pps_mutex);
> +	edp_pps_unlock(intel_dp);
>  
>  	return ret;
>  }
> @@ -1312,16 +1369,14 @@ static bool edp_panel_vdd_on(struct intel_dp *intel_dp)
>  
>  void intel_edp_panel_vdd_on(struct intel_dp *intel_dp)
>  {
> -	struct drm_i915_private *dev_priv =
> -		intel_dp_to_dev(intel_dp)->dev_private;
>  	bool vdd;
>  
>  	if (!is_edp(intel_dp))
>  		return;
>  
> -	mutex_lock(&dev_priv->pps_mutex);
> +	edp_pps_lock(intel_dp);
>  	vdd = edp_panel_vdd_on(intel_dp);
> -	mutex_unlock(&dev_priv->pps_mutex);
> +	edp_pps_unlock(intel_dp);
>  
>  	WARN(!vdd, "eDP VDD already requested on\n");
>  }
> @@ -1370,13 +1425,11 @@ static void edp_panel_vdd_work(struct work_struct *__work)
>  {
>  	struct intel_dp *intel_dp = container_of(to_delayed_work(__work),
>  						 struct intel_dp, panel_vdd_work);
> -	struct drm_i915_private *dev_priv =
> -		intel_dp_to_dev(intel_dp)->dev_private;
>  
> -	mutex_lock(&dev_priv->pps_mutex);
> +	edp_pps_lock(intel_dp);
>  	if (!intel_dp->want_panel_vdd)
>  		edp_panel_vdd_off_sync(intel_dp);
> -	mutex_unlock(&dev_priv->pps_mutex);
> +	edp_pps_unlock(intel_dp);
>  }
>  
>  static void edp_panel_vdd_schedule_off(struct intel_dp *intel_dp)
> @@ -1414,15 +1467,12 @@ static void edp_panel_vdd_off(struct intel_dp *intel_dp, bool sync)
>  
>  static void intel_edp_panel_vdd_off(struct intel_dp *intel_dp, bool sync)
>  {
> -	struct drm_i915_private *dev_priv =
> -		intel_dp_to_dev(intel_dp)->dev_private;
> -
>  	if (!is_edp(intel_dp))
>  		return;
>  
> -	mutex_lock(&dev_priv->pps_mutex);
> +	edp_pps_lock(intel_dp);
>  	edp_panel_vdd_off(intel_dp, sync);
> -	mutex_unlock(&dev_priv->pps_mutex);
> +	edp_pps_unlock(intel_dp);
>  }
>  
>  void intel_edp_panel_on(struct intel_dp *intel_dp)
> @@ -1437,7 +1487,7 @@ void intel_edp_panel_on(struct intel_dp *intel_dp)
>  
>  	DRM_DEBUG_KMS("Turn eDP power on\n");
>  
> -	mutex_lock(&dev_priv->pps_mutex);
> +	edp_pps_lock(intel_dp);
>  
>  	if (edp_have_panel_power(intel_dp)) {
>  		DRM_DEBUG_KMS("eDP power already on\n");
> @@ -1472,7 +1522,7 @@ void intel_edp_panel_on(struct intel_dp *intel_dp)
>  	}
>  
>   out:
> -	mutex_unlock(&dev_priv->pps_mutex);
> +	edp_pps_unlock(intel_dp);
>  }
>  
>  void intel_edp_panel_off(struct intel_dp *intel_dp)
> @@ -1490,7 +1540,7 @@ void intel_edp_panel_off(struct intel_dp *intel_dp)
>  
>  	DRM_DEBUG_KMS("Turn eDP power off\n");
>  
> -	mutex_lock(&dev_priv->pps_mutex);
> +	edp_pps_lock(intel_dp);
>  
>  	WARN(!intel_dp->want_panel_vdd, "Need VDD to turn off panel\n");
>  
> @@ -1514,7 +1564,7 @@ void intel_edp_panel_off(struct intel_dp *intel_dp)
>  	power_domain = intel_display_port_power_domain(intel_encoder);
>  	intel_display_power_put(dev_priv, power_domain);
>  
> -	mutex_unlock(&dev_priv->pps_mutex);
> +	edp_pps_unlock(intel_dp);
>  }
>  
>  void intel_edp_backlight_on(struct intel_dp *intel_dp)
> @@ -1540,7 +1590,7 @@ void intel_edp_backlight_on(struct intel_dp *intel_dp)
>  	 */
>  	wait_backlight_on(intel_dp);
>  
> -	mutex_lock(&dev_priv->pps_mutex);
> +	edp_pps_lock(intel_dp);
>  
>  	pp = ironlake_get_pp_control(intel_dp);
>  	pp |= EDP_BLC_ENABLE;
> @@ -1550,7 +1600,7 @@ void intel_edp_backlight_on(struct intel_dp *intel_dp)
>  	I915_WRITE(pp_ctrl_reg, pp);
>  	POSTING_READ(pp_ctrl_reg);
>  
> -	mutex_unlock(&dev_priv->pps_mutex);
> +	edp_pps_unlock(intel_dp);
>  }
>  
>  void intel_edp_backlight_off(struct intel_dp *intel_dp)
> @@ -1563,7 +1613,7 @@ void intel_edp_backlight_off(struct intel_dp *intel_dp)
>  	if (!is_edp(intel_dp))
>  		return;
>  
> -	mutex_lock(&dev_priv->pps_mutex);
> +	edp_pps_lock(intel_dp);
>  
>  	DRM_DEBUG_KMS("\n");
>  	pp = ironlake_get_pp_control(intel_dp);
> @@ -1574,7 +1624,7 @@ void intel_edp_backlight_off(struct intel_dp *intel_dp)
>  	I915_WRITE(pp_ctrl_reg, pp);
>  	POSTING_READ(pp_ctrl_reg);
>  
> -	mutex_unlock(&dev_priv->pps_mutex);
> +	edp_pps_unlock(intel_dp);
>  
>  	intel_dp->last_backlight_off = jiffies;
>  	edp_wait_backlight_off(intel_dp);

As in 9/14 the changes in the backlight functions and in
edp_notifier_handler() need to be rebased, with that this patch looks
ok:
Reviewed-by: Imre Deak <imre.deak@intel.com>

> @@ -2290,18 +2340,19 @@ static void vlv_steal_power_sequencer(struct drm_device *dev,
>  
>  	list_for_each_entry(encoder, &dev->mode_config.encoder_list, base.head) {
>  		struct intel_dp *intel_dp;
> +		enum port port;
>  
>  		if (encoder->type != INTEL_OUTPUT_EDP)
>  			continue;
>  
>  		intel_dp = enc_to_intel_dp(&encoder->base);
> +		port = dp_to_dig_port(intel_dp)->port;
>  
>  		if (intel_dp->pps_pipe != pipe)
>  			continue;
>  
>  		DRM_DEBUG_KMS("stealing pipe %c power sequencer from port %c\n",
> -			      pipe_name(pipe),
> -			      port_name(dp_to_dig_port(intel_dp)->port));
> +			      pipe_name(pipe), port_name(port));
>  
>  		/* make sure vdd is off before we steal it */
>  		edp_panel_vdd_off_sync(intel_dp);
> @@ -2377,9 +2428,9 @@ static void vlv_pre_enable_dp(struct intel_encoder *encoder)
>  	mutex_unlock(&dev_priv->dpio_lock);
>  
>  	if (is_edp(intel_dp)) {
> -		mutex_lock(&dev_priv->pps_mutex);
> +		edp_pps_lock(intel_dp);
>  		vlv_init_panel_power_sequencer(intel_dp);
> -		mutex_unlock(&dev_priv->pps_mutex);
> +		edp_pps_unlock(intel_dp);
>  	}
>  
>  	intel_enable_dp(encoder);
> @@ -2477,9 +2528,9 @@ static void chv_pre_enable_dp(struct intel_encoder *encoder)
>  	mutex_unlock(&dev_priv->dpio_lock);
>  
>  	if (is_edp(intel_dp)) {
> -		mutex_lock(&dev_priv->pps_mutex);
> +		edp_pps_lock(intel_dp);
>  		vlv_init_panel_power_sequencer(intel_dp);
> -		mutex_unlock(&dev_priv->pps_mutex);
> +		edp_pps_unlock(intel_dp);
>  	}
>  
>  	intel_enable_dp(encoder);
> @@ -4219,17 +4270,16 @@ void intel_dp_encoder_destroy(struct drm_encoder *encoder)
>  {
>  	struct intel_digital_port *intel_dig_port = enc_to_dig_port(encoder);
>  	struct intel_dp *intel_dp = &intel_dig_port->dp;
> -	struct drm_device *dev = intel_dp_to_dev(intel_dp);
> -	struct drm_i915_private *dev_priv = dev->dev_private;
>  
>  	drm_dp_aux_unregister(&intel_dp->aux);
>  	intel_dp_mst_encoder_cleanup(intel_dig_port);
>  	drm_encoder_cleanup(encoder);
>  	if (is_edp(intel_dp)) {
>  		cancel_delayed_work_sync(&intel_dp->panel_vdd_work);
> -		mutex_lock(&dev_priv->pps_mutex);
> +		edp_pps_lock(intel_dp);
>  		edp_panel_vdd_off_sync(intel_dp);
> -		mutex_unlock(&dev_priv->pps_mutex);
> +		edp_pps_unlock(intel_dp);
> +
>  		if (intel_dp->edp_notifier.notifier_call) {
>  			unregister_reboot_notifier(&intel_dp->edp_notifier);
>  			intel_dp->edp_notifier.notifier_call = NULL;
> @@ -4241,15 +4291,13 @@ void intel_dp_encoder_destroy(struct drm_encoder *encoder)
>  static void intel_dp_encoder_suspend(struct intel_encoder *intel_encoder)
>  {
>  	struct intel_dp *intel_dp = enc_to_intel_dp(&intel_encoder->base);
> -	struct drm_device *dev = intel_dp_to_dev(intel_dp);
> -	struct drm_i915_private *dev_priv = dev->dev_private;
>  
>  	if (!is_edp(intel_dp))
>  		return;
>  
> -	mutex_lock(&dev_priv->pps_mutex);
> +	edp_pps_lock(intel_dp);
>  	edp_panel_vdd_off_sync(intel_dp);
> -	mutex_unlock(&dev_priv->pps_mutex);
> +	edp_pps_unlock(intel_dp);
>  }
>  
>  static void intel_dp_encoder_reset(struct drm_encoder *encoder)
> @@ -4727,9 +4775,10 @@ void intel_edp_panel_vdd_sanitize(struct intel_encoder *intel_encoder)
>  	if (intel_encoder->type != INTEL_OUTPUT_EDP)
>  		return;
>  
> -	mutex_lock(&dev_priv->pps_mutex);
> -
>  	intel_dp = enc_to_intel_dp(&intel_encoder->base);
> +
> +	edp_pps_lock(intel_dp);
> +
>  	if (!edp_have_panel_vdd(intel_dp))
>  		goto out;
>  	/*
> @@ -4744,7 +4793,7 @@ void intel_edp_panel_vdd_sanitize(struct intel_encoder *intel_encoder)
>  
>  	edp_panel_vdd_schedule_off(intel_dp);
>   out:
> -	mutex_unlock(&dev_priv->pps_mutex);
> +	edp_pps_unlock(intel_dp);
>  }
>  
>  static bool intel_edp_init_connector(struct intel_dp *intel_dp,
> @@ -4786,9 +4835,9 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
>  	}
>  
>  	/* We now know it's not a ghost, init power sequence regs. */
> -	mutex_lock(&dev_priv->pps_mutex);
> +	edp_pps_lock(intel_dp);
>  	intel_dp_init_panel_power_sequencer_registers(dev, intel_dp, power_seq);
> -	mutex_unlock(&dev_priv->pps_mutex);
> +	edp_pps_unlock(intel_dp);
>  
>  	mutex_lock(&dev->mode_config.mutex);
>  	edid = drm_get_edid(connector, &intel_dp->aux.ddc);
> @@ -4922,14 +4971,14 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
>  	}
>  
>  	if (is_edp(intel_dp)) {
> -		mutex_lock(&dev_priv->pps_mutex);
> +		edp_pps_lock(intel_dp);
>  		if (IS_VALLEYVIEW(dev)) {
>  			vlv_initial_power_sequencer_setup(intel_dp);
>  		} else {
>  			intel_dp_init_panel_power_timestamps(intel_dp);
>  			intel_dp_init_panel_power_sequencer(dev, intel_dp, &power_seq);
>  		}
> -		mutex_unlock(&dev_priv->pps_mutex);
> +		edp_pps_unlock(intel_dp);
>  	}
>  
>  	intel_dp_aux_init(intel_dp, intel_connector);
> @@ -4945,9 +4994,9 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
>  		drm_dp_aux_unregister(&intel_dp->aux);
>  		if (is_edp(intel_dp)) {
>  			cancel_delayed_work_sync(&intel_dp->panel_vdd_work);
> -			mutex_lock(&dev_priv->pps_mutex);
> +			edp_pps_lock(intel_dp);
>  			edp_panel_vdd_off_sync(intel_dp);
> -			mutex_unlock(&dev_priv->pps_mutex);
> +			edp_pps_unlock(intel_dp);
>  		}
>  		drm_connector_unregister(connector);
>  		drm_connector_cleanup(connector);
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 849a447..32627ae 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -943,6 +943,7 @@ void intel_dp_mst_suspend(struct drm_device *dev);
>  void intel_dp_mst_resume(struct drm_device *dev);
>  int intel_dp_max_link_bw(struct intel_dp *intel_dp);
>  void intel_dp_hot_plug(struct intel_encoder *intel_encoder);
> +void vlv_power_sequencer_reset(struct drm_i915_private *dev_priv);
>  /* intel_dp_mst.c */
>  int intel_dp_mst_encoder_init(struct intel_digital_port *intel_dig_port, int conn_id);
>  void intel_dp_mst_encoder_cleanup(struct intel_digital_port *intel_dig_port);
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 39dd066..d5ffda9 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -6328,6 +6328,8 @@ static void vlv_display_power_well_disable(struct drm_i915_private *dev_priv,
>  	spin_unlock_irq(&dev_priv->irq_lock);
>  
>  	vlv_set_power_well(dev_priv, power_well, false);
> +
> +	vlv_power_sequencer_reset(dev_priv);
>  }
>  
>  static void vlv_dpio_cmn_power_well_enable(struct drm_i915_private *dev_priv,