drm/i915/dp: Restore PPS HW state from the encoder resume hook

Similarly to the previous patch, initialize the PPS from the DP
encoder's resume hook. Note that as opposed to LVDS we can't do this
during encoder enabling, since we need the PPS for DP detection as well.
The PPS init code is now the same for init and resume, so factor out a
new intel_dp_pps_init() helper for this.

v2:
- Factor out intel_dp_pps_init() (Ville).
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470827254-21954-4-git-send-email-imre.deak@intel.com

drivers/gpu/drm/i915/intel_dp.c

@@ -256,6 +256,8 @@ intel_dp_init_panel_power_sequencer(struct drm_device *dev,
 static void
 intel_dp_init_panel_power_sequencer_registers(struct drm_device *dev,
 					      struct intel_dp *intel_dp);
+static void
+intel_dp_pps_init(struct drm_device *dev, struct intel_dp *intel_dp);
 
 static void pps_lock(struct intel_dp *intel_dp)
 {
@@ -4657,13 +4659,8 @@ void intel_dp_encoder_reset(struct drm_encoder *encoder)
 
 	pps_lock(intel_dp);
 
-	/*
-	 * Read out the current power sequencer assignment,
-	 * in case the BIOS did something with it.
-	 */
-	if (IS_VALLEYVIEW(encoder->dev) || IS_CHERRYVIEW(encoder->dev))
-		vlv_initial_power_sequencer_setup(intel_dp);
-
+	/* Reinit the power sequencer, in case BIOS did something with it. */
+	intel_dp_pps_init(encoder->dev, intel_dp);
 	intel_edp_panel_vdd_sanitize(intel_dp);
 
 	pps_unlock(intel_dp);
@@ -5011,6 +5008,17 @@ intel_dp_init_panel_power_sequencer_registers(struct drm_device *dev,
 		      I915_READ(regs.pp_div));
 }
 
+static void intel_dp_pps_init(struct drm_device *dev,
+			      struct intel_dp *intel_dp)
+{
+	if (IS_VALLEYVIEW(dev) || IS_CHERRYVIEW(dev)) {
+		vlv_initial_power_sequencer_setup(intel_dp);
+	} else {
+		intel_dp_init_panel_power_sequencer(dev, intel_dp);
+		intel_dp_init_panel_power_sequencer_registers(dev, intel_dp);
+	}
+}
+
 /**
  * intel_dp_set_drrs_state - program registers for RR switch to take effect
  * @dev: DRM device
@@ -5425,14 +5433,7 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
 	pps_lock(intel_dp);
 
 	intel_dp_init_panel_power_timestamps(intel_dp);
-
-	if (IS_VALLEYVIEW(dev) || IS_CHERRYVIEW(dev)) {
-		vlv_initial_power_sequencer_setup(intel_dp);
-	} else {
-		intel_dp_init_panel_power_sequencer(dev, intel_dp);
-		intel_dp_init_panel_power_sequencer_registers(dev, intel_dp);
-	}
-
+	intel_dp_pps_init(dev, intel_dp);
 	intel_edp_panel_vdd_sanitize(intel_dp);
 
 	pps_unlock(intel_dp);