drm/i915: Track power reference taken for eDP VDD

Add wakeref tracking for the eDP encoders' AUX display power domain
references taken while the panel's VDD is enabled.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20201130212200.2811939-7-imre.deak@intel.com

drivers/gpu/drm/i915/display/intel_display_types.h

@@ -1384,6 +1384,7 @@ struct intel_dp {
 	unsigned long last_power_on;
 	unsigned long last_backlight_off;
 	ktime_t panel_power_off_time;
+	intel_wakeref_t vdd_wakeref;
 
 	/*
 	 * Pipe whose power sequencer is currently locked into

drivers/gpu/drm/i915/display/intel_dp.c

@@ -3094,7 +3094,8 @@ static bool edp_panel_vdd_on(struct intel_dp *intel_dp)
 	if (edp_have_panel_vdd(intel_dp))
 		return need_to_disable;
 
-	intel_display_power_get(dev_priv,
+	drm_WARN_ON(&dev_priv->drm, intel_dp->vdd_wakeref);
+	intel_dp->vdd_wakeref = intel_display_power_get(dev_priv,
 							intel_aux_power_domain(dig_port));
 
 	drm_dbg_kms(&dev_priv->drm, "Turning [ENCODER:%d:%s] VDD on\n",
@@ -3188,8 +3189,9 @@ static void edp_panel_vdd_off_sync(struct intel_dp *intel_dp)
 	if ((pp & PANEL_POWER_ON) == 0)
 		intel_dp->panel_power_off_time = ktime_get_boottime();
 
-	intel_display_power_put_unchecked(dev_priv,
-					  intel_aux_power_domain(dig_port));
+	intel_display_power_put(dev_priv,
+				intel_aux_power_domain(dig_port),
+				fetch_and_zero(&intel_dp->vdd_wakeref));
 }
 
 static void edp_panel_vdd_work(struct work_struct *__work)
@@ -3341,7 +3343,9 @@ static void edp_panel_off(struct intel_dp *intel_dp)
 	intel_dp->panel_power_off_time = ktime_get_boottime();
 
 	/* We got a reference when we enabled the VDD. */
-	intel_display_power_put_unchecked(dev_priv, intel_aux_power_domain(dig_port));
+	intel_display_power_put(dev_priv,
+				intel_aux_power_domain(dig_port),
+				fetch_and_zero(&intel_dp->vdd_wakeref));
 }
 
 void intel_edp_panel_off(struct intel_dp *intel_dp)
@@ -6894,7 +6898,9 @@ static void intel_edp_panel_vdd_sanitize(struct intel_dp *intel_dp)
 	 */
 	drm_dbg_kms(&dev_priv->drm,
 		    "VDD left on by BIOS, adjusting state tracking\n");
-	intel_display_power_get(dev_priv, intel_aux_power_domain(dig_port));
+	drm_WARN_ON(&dev_priv->drm, intel_dp->vdd_wakeref);
+	intel_dp->vdd_wakeref = intel_display_power_get(dev_priv,
+							intel_aux_power_domain(dig_port));
 
 	edp_panel_vdd_schedule_off(intel_dp);
 }