drm/i915/backlight: Restore backlight on resume, v3.

Restore our saved values for backlight. This way even with fastset on
S4 resume we will correctly restore the backlight to the active values.

Changes since v1:
- Call enable_backlight() when backlight.level is set. On suspend
  backlight.enabled is always cleared, this makes it not a good
  indicator. Also check for crtc->state->active.
Changes since v2:
- Use the new update_pipe() callback to run this on resume as well.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Tolga Cakir <cevelnet@gmail.com>
Cc: Basil Eric Rabi <ericbasil.rabi@gmail.com>
Cc: Hans de Goede <jwrdegoede@fedoraproject.org>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190108160842.13396-1-maarten.lankhorst@linux.intel.com

drivers/gpu/drm/i915/icl_dsi.c

@@ -1390,6 +1390,7 @@ void icl_dsi_init(struct drm_i915_private *dev_priv)
 	encoder->disable = gen11_dsi_disable;
 	encoder->port = port;
 	encoder->get_config = gen11_dsi_get_config;
+	encoder->update_pipe = intel_panel_update_backlight;
 	encoder->compute_config = gen11_dsi_compute_config;
 	encoder->get_hw_state = gen11_dsi_get_hw_state;
 	encoder->type = INTEL_OUTPUT_DSI;

drivers/gpu/drm/i915/intel_ddi.c

@@ -3556,6 +3556,8 @@ static void intel_ddi_update_pipe_dp(struct intel_encoder *encoder,
 
 	intel_psr_enable(intel_dp, crtc_state);
 	intel_edp_drrs_enable(intel_dp, crtc_state);
+
+	intel_panel_update_backlight(encoder, crtc_state, conn_state);
 }
 
 static void intel_ddi_update_pipe(struct intel_encoder *encoder,

drivers/gpu/drm/i915/intel_dp.c

@@ -7001,6 +7001,7 @@ bool intel_dp_init(struct drm_i915_private *dev_priv,
 	intel_encoder->compute_config = intel_dp_compute_config;
 	intel_encoder->get_hw_state = intel_dp_get_hw_state;
 	intel_encoder->get_config = intel_dp_get_config;
+	intel_encoder->update_pipe = intel_panel_update_backlight;
 	intel_encoder->suspend = intel_dp_encoder_suspend;
 	if (IS_CHERRYVIEW(dev_priv)) {
 		intel_encoder->pre_pll_enable = chv_dp_pre_pll_enable;

drivers/gpu/drm/i915/intel_drv.h

@@ -2023,6 +2023,9 @@ int intel_panel_setup_backlight(struct drm_connector *connector,
 				enum pipe pipe);
 void intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state,
 				  const struct drm_connector_state *conn_state);
+void intel_panel_update_backlight(struct intel_encoder *encoder,
+				  const struct intel_crtc_state *crtc_state,
+				  const struct drm_connector_state *conn_state);
 void intel_panel_disable_backlight(const struct drm_connector_state *old_conn_state);
 extern struct drm_display_mode *intel_find_panel_downclock(
 				struct drm_i915_private *dev_priv,

drivers/gpu/drm/i915/intel_lvds.c

@@ -887,6 +887,7 @@ void intel_lvds_init(struct drm_i915_private *dev_priv)
 	}
 	intel_encoder->get_hw_state = intel_lvds_get_hw_state;
 	intel_encoder->get_config = intel_lvds_get_config;
+	intel_encoder->update_pipe = intel_panel_update_backlight;
 	intel_connector->get_hw_state = intel_connector_get_hw_state;
 
 	intel_connector_attach_encoder(intel_connector, intel_encoder);

drivers/gpu/drm/i915/intel_panel.c

@@ -1087,20 +1087,11 @@ static void pwm_enable_backlight(const struct intel_crtc_state *crtc_state,
 	intel_panel_actually_set_backlight(conn_state, panel->backlight.level);
 }
 
-void intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state,
-				  const struct drm_connector_state *conn_state)
+static void __intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state,
+					   const struct drm_connector_state *conn_state)
 {
 	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
 	struct intel_panel *panel = &connector->panel;
-	enum pipe pipe = to_intel_crtc(crtc_state->base.crtc)->pipe;
-
-	if (!panel->backlight.present)
-		return;
-
-	DRM_DEBUG_KMS("pipe %c\n", pipe_name(pipe));
-
-	mutex_lock(&dev_priv->backlight_lock);
 
 	WARN_ON(panel->backlight.max == 0);
 
@@ -1117,6 +1108,24 @@ void intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state,
 	panel->backlight.enabled = true;
 	if (panel->backlight.device)
 		panel->backlight.device->props.power = FB_BLANK_UNBLANK;
+}
+
+void intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state,
+				  const struct drm_connector_state *conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	enum pipe pipe = to_intel_crtc(crtc_state->base.crtc)->pipe;
+
+	if (!panel->backlight.present)
+		return;
+
+	DRM_DEBUG_KMS("pipe %c\n", pipe_name(pipe));
+
+	mutex_lock(&dev_priv->backlight_lock);
+
+	__intel_panel_enable_backlight(crtc_state, conn_state);
 
 	mutex_unlock(&dev_priv->backlight_lock);
 }
@@ -1776,6 +1785,24 @@ static int pwm_setup_backlight(struct intel_connector *connector,
 	return 0;
 }
 
+void intel_panel_update_backlight(struct intel_encoder *encoder,
+				  const struct intel_crtc_state *crtc_state,
+				  const struct drm_connector_state *conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+
+	if (!panel->backlight.present)
+		return;
+
+	mutex_lock(&dev_priv->backlight_lock);
+	if (!panel->backlight.enabled)
+		__intel_panel_enable_backlight(crtc_state, conn_state);
+
+	mutex_unlock(&dev_priv->backlight_lock);
+}
+
 int intel_panel_setup_backlight(struct drm_connector *connector, enum pipe pipe)
 {
 	struct drm_i915_private *dev_priv = to_i915(connector->dev);

drivers/gpu/drm/i915/vlv_dsi.c

@@ -1697,6 +1697,7 @@ void vlv_dsi_init(struct drm_i915_private *dev_priv)
 	intel_encoder->post_disable = intel_dsi_post_disable;
 	intel_encoder->get_hw_state = intel_dsi_get_hw_state;
 	intel_encoder->get_config = intel_dsi_get_config;
+	intel_encoder->update_pipe = intel_panel_update_backlight;
 
 	intel_connector->get_hw_state = intel_connector_get_hw_state;