drm/i915: Try to use the correct power sequencer intiially on bxt/glk

Currently on bxt/glk we just grab the power sequencer index from
the VBT data even though it may not have been parsed yet. That
could lead us to using the incorrect power sequencer during the
initial panel probe.

To avoid that let's try to read out the current state of the
power sequencer from the hardware. Unfortunately the power
sequencer no longer has anything in its registers to associate
it with the port, so the best we can do is just iterate through
the power sequencers and pick the first one. This should be
sufficient for single panel cases.

For the dual panel cases we probably need to go back to
parsing the VBT before the panel probe (and hope that
panel_type=0xff is never a thing in those cases). To that
end the code always prefers the VBT panel sequencer, if
available.

v2: Restructure a bit for upcoming icp+ dual PPS support

Cc: Animesh Manna <animesh.manna@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221125173156.31689-5-ville.syrjala@linux.intel.comReviewed-by: Animesh Manna <animesh.manna@intel.com>

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

@@ -330,7 +330,7 @@ struct intel_vbt_panel_data {
 		bool present;
 		bool active_low_pwm;
 		u8 min_brightness;	/* min_brightness/255 of max */
-		u8 controller;		/* brightness controller number */
+		s8 controller;		/* brightness controller number */
 		enum intel_backlight_type type;
 	} backlight;
 
@@ -1570,11 +1570,19 @@ struct intel_pps {
 	ktime_t panel_power_off_time;
 	intel_wakeref_t vdd_wakeref;
 
+	union {
 		/*
 		 * Pipe whose power sequencer is currently locked into
 		 * this port. Only relevant on VLV/CHV.
 		 */
 		enum pipe pps_pipe;
+
+		/*
+		 * Power sequencer index. Only relevant on BXT+.
+		 */
+		int pps_idx;
+	};
+
 	/*
 	 * Pipe currently driving the port. Used for preventing
 	 * the use of the PPS for any pipe currentrly driving
@@ -1583,7 +1591,7 @@ struct intel_pps {
 	enum pipe active_pipe;
 	/*
 	 * Set if the sequencer may be reset due to a power transition,
-	 * requiring a reinitialization. Only relevant on BXT.
+	 * requiring a reinitialization. Only relevant on BXT+.
 	 */
 	bool pps_reset;
 	struct edp_power_seq pps_delays;

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

@@ -666,6 +666,7 @@ void intel_panel_init_alloc(struct intel_connector *connector)
 	struct intel_panel *panel = &connector->panel;
 
 	connector->panel.vbt.panel_type = -1;
+	connector->panel.vbt.backlight.controller = -1;
 	INIT_LIST_HEAD(&panel->fixed_modes);
 }
 

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

@@ -212,8 +212,7 @@ static int
 bxt_power_sequencer_idx(struct intel_dp *intel_dp)
 {
 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
-	struct intel_connector *connector = intel_dp->attached_connector;
-	int backlight_controller = connector->panel.vbt.backlight.controller;
+	int pps_idx = intel_dp->pps.pps_idx;
 
 	lockdep_assert_held(&dev_priv->display.pps.mutex);
 
@@ -221,7 +220,7 @@ bxt_power_sequencer_idx(struct intel_dp *intel_dp)
 	drm_WARN_ON(&dev_priv->drm, !intel_dp_is_edp(intel_dp));
 
 	if (!intel_dp->pps.pps_reset)
-		return backlight_controller;
+		return pps_idx;
 
 	intel_dp->pps.pps_reset = false;
 
@@ -231,7 +230,7 @@ bxt_power_sequencer_idx(struct intel_dp *intel_dp)
 	 */
 	pps_init_registers(intel_dp, false);
 
-	return backlight_controller;
+	return pps_idx;
 }
 
 typedef bool (*pps_check)(struct drm_i915_private *dev_priv, int pps_idx);
@@ -311,6 +310,64 @@ vlv_initial_power_sequencer_setup(struct intel_dp *intel_dp)
 		    pipe_name(intel_dp->pps.pps_pipe));
 }
 
+static int
+bxt_initial_pps_idx(struct drm_i915_private *i915, pps_check check)
+{
+	int pps_idx, pps_num = 2;
+
+	for (pps_idx = 0; pps_idx < pps_num; pps_idx++) {
+		if (check(i915, pps_idx))
+			return pps_idx;
+	}
+
+	return -1;
+}
+
+static void
+pps_initial_setup(struct intel_dp *intel_dp)
+{
+	struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base;
+	struct intel_connector *connector = intel_dp->attached_connector;
+	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
+
+	lockdep_assert_held(&i915->display.pps.mutex);
+
+	if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915)) {
+		vlv_initial_power_sequencer_setup(intel_dp);
+		return;
+	}
+
+	if (!IS_GEMINILAKE(i915) && !IS_BROXTON(i915))
+		return;
+
+	/* first ask the VBT */
+	intel_dp->pps.pps_idx = connector->panel.vbt.backlight.controller;
+	if (drm_WARN_ON(&i915->drm, intel_dp->pps.pps_idx >= 2))
+		intel_dp->pps.pps_idx = -1;
+
+	/* VBT wasn't parsed yet? pick one where the panel is on */
+	if (intel_dp->pps.pps_idx < 0)
+		intel_dp->pps.pps_idx = bxt_initial_pps_idx(i915, pps_has_pp_on);
+	/* didn't find one? pick one where vdd is on */
+	if (intel_dp->pps.pps_idx < 0)
+		intel_dp->pps.pps_idx = bxt_initial_pps_idx(i915, pps_has_vdd_on);
+	/* didn't find one? pick any */
+	if (intel_dp->pps.pps_idx < 0) {
+		intel_dp->pps.pps_idx = bxt_initial_pps_idx(i915, pps_any);
+
+		drm_dbg_kms(&i915->drm,
+			    "[ENCODER:%d:%s] no initial power sequencer, assuming %d\n",
+			    encoder->base.base.id, encoder->base.name,
+			    intel_dp->pps.pps_idx);
+		return;
+	}
+
+	drm_dbg_kms(&i915->drm,
+		    "[ENCODER:%d:%s] initial power sequencer: %d\n",
+		    encoder->base.base.id, encoder->base.name,
+		    intel_dp->pps.pps_idx);
+}
+
 void intel_pps_reset_all(struct drm_i915_private *dev_priv)
 {
 	struct intel_encoder *encoder;
@@ -363,10 +420,10 @@ static void intel_pps_get_registers(struct intel_dp *intel_dp,
 
 	memset(regs, 0, sizeof(*regs));
 
-	if (IS_GEMINILAKE(dev_priv) || IS_BROXTON(dev_priv))
-		pps_idx = bxt_power_sequencer_idx(intel_dp);
-	else if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
+	if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
 		pps_idx = vlv_power_sequencer_pipe(intel_dp);
+	else if (IS_GEMINILAKE(dev_priv) || IS_BROXTON(dev_priv))
+		pps_idx = bxt_power_sequencer_idx(intel_dp);
 
 	regs->pp_ctrl = PP_CONTROL(pps_idx);
 	regs->pp_stat = PP_STATUS(pps_idx);
@@ -1429,7 +1486,6 @@ void intel_pps_encoder_reset(struct intel_dp *intel_dp)
 
 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;
@@ -1438,8 +1494,7 @@ void intel_pps_init(struct intel_dp *intel_dp)
 	pps_init_timestamps(intel_dp);
 
 	with_intel_pps_lock(intel_dp, wakeref) {
-		if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915))
-			vlv_initial_power_sequencer_setup(intel_dp);
+		pps_initial_setup(intel_dp);
 
 		pps_init_delays(intel_dp);
 		pps_init_registers(intel_dp, false);
@@ -1447,12 +1502,33 @@ void intel_pps_init(struct intel_dp *intel_dp)
 	}
 }
 
+static void pps_init_late(struct intel_dp *intel_dp)
+{
+	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
+	struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base;
+	struct intel_connector *connector = intel_dp->attached_connector;
+
+	if (!IS_GEMINILAKE(i915) && !IS_BROXTON(i915))
+		return;
+
+	drm_WARN(&i915->drm, connector->panel.vbt.backlight.controller >= 0 &&
+		 intel_dp->pps.pps_idx != connector->panel.vbt.backlight.controller,
+		 "[ENCODER:%d:%s] power sequencer mismatch: %d (initial) vs. %d (VBT)\n",
+		 encoder->base.base.id, encoder->base.name,
+		 intel_dp->pps.pps_idx, connector->panel.vbt.backlight.controller);
+
+	if (connector->panel.vbt.backlight.controller >= 0)
+		intel_dp->pps.pps_idx = connector->panel.vbt.backlight.controller;
+}
+
 void intel_pps_init_late(struct intel_dp *intel_dp)
 {
 	intel_wakeref_t wakeref;
 
 	with_intel_pps_lock(intel_dp, wakeref) {
 		/* Reinit delays after per-panel info has been parsed from VBT */
+		pps_init_late(intel_dp);
+
 		memset(&intel_dp->pps.pps_delays, 0, sizeof(intel_dp->pps.pps_delays));
 		pps_init_delays(intel_dp);
 		pps_init_registers(intel_dp, false);