drm/i915/pps: Keep VDD enabled during eDP probe

Disable the delayed VDD off work during the eDP probe.
If we never turn off the VDD then we can't violate the
panel's power sequencing delays despite not having read
them out yet from the VBT.

This is mostly a belt+suspenders type of thing since the
the timeout we'd use for the delayed work should be long
enough that this won't normally happen. But I don't really
like relying on timeouts for correctless so might as well
make sure.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220510104242.6099-10-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

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

@@ -1474,6 +1474,7 @@ struct intel_pps {
 	int backlight_off_delay;
 	struct delayed_work panel_vdd_work;
 	bool want_panel_vdd;
+	bool initializing;
 	unsigned long last_power_on;
 	unsigned long last_backlight_off;
 	ktime_t panel_power_off_time;

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

@@ -722,6 +722,13 @@ static void edp_panel_vdd_schedule_off(struct intel_dp *intel_dp)
 {
 	unsigned long delay;
 
+	/*
+	 * We may not yet know the real power sequencing delays,
+	 * so keep VDD enabled until we're done with init.
+	 */
+	if (intel_dp->pps.initializing)
+		return;
+
 	/*
 	 * Queue the timer to fire a long time from now (relative to the power
 	 * down delay) to keep the panel power up across a sequence of
@@ -1419,6 +1426,7 @@ void intel_pps_init(struct intel_dp *intel_dp)
 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
 	intel_wakeref_t wakeref;
 
+	intel_dp->pps.initializing = true;
 	INIT_DELAYED_WORK(&intel_dp->pps.panel_vdd_work, edp_panel_vdd_work);
 
 	pps_init_timestamps(intel_dp);
@@ -1443,6 +1451,8 @@ void intel_pps_init_late(struct intel_dp *intel_dp)
 		pps_init_delays(intel_dp);
 		pps_init_registers(intel_dp, false);
 
+		intel_dp->pps.initializing = false;
+
 		if (edp_have_panel_vdd(intel_dp))
 			edp_panel_vdd_schedule_off(intel_dp);
 	}