drm/i915: convert INTEL_DISPLAY_ENABLED() into a function

There's no need for this to be a macro. Add some documentation too.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/480b9b697b2ffa0c8677115bd443ba633801c6c1.1696336887.git.jani.nikula@intel.com

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

@@ -838,7 +838,7 @@ intel_crt_detect(struct drm_connector *connector,
 		    connector->base.id, connector->name,
 		    force);
 
-	if (!INTEL_DISPLAY_ENABLED(dev_priv))
+	if (!intel_display_device_enabled(dev_priv))
 		return connector_status_disconnected;
 
 	if (dev_priv->params.load_detect_test) {

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

@@ -1091,3 +1091,20 @@ void intel_display_device_info_print(const struct intel_display_device_info *inf
 	drm_printf(p, "has_dmc: %s\n", str_yes_no(runtime->has_dmc));
 	drm_printf(p, "has_dsc: %s\n", str_yes_no(runtime->has_dsc));
 }
+
+/*
+ * Assuming the device has display hardware, should it be enabled?
+ *
+ * It's an error to call this function if the device does not have display
+ * hardware.
+ *
+ * Disabling display means taking over the display hardware, putting it to
+ * sleep, and preventing connectors from being connected via any means.
+ */
+bool intel_display_device_enabled(struct drm_i915_private *i915)
+{
+	/* Only valid when HAS_DISPLAY() is true */
+	drm_WARN_ON(&i915->drm, !HAS_DISPLAY(i915));
+
+	return !i915->params.disable_display && !intel_opregion_headless_sku(i915);
+}

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

@@ -150,6 +150,7 @@ struct intel_display_device_info {
 	} color;
 };
 
+bool intel_display_device_enabled(struct drm_i915_private *i915);
 void intel_display_device_probe(struct drm_i915_private *i915);
 void intel_display_device_info_runtime_init(struct drm_i915_private *i915);
 

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

@@ -5358,7 +5358,7 @@ intel_dp_detect(struct drm_connector *connector,
 	drm_WARN_ON(&dev_priv->drm,
 		    !drm_modeset_is_locked(&dev_priv->drm.mode_config.connection_mutex));
 
-	if (!INTEL_DISPLAY_ENABLED(dev_priv))
+	if (!intel_display_device_enabled(dev_priv))
 		return connector_status_disconnected;
 
 	/* Can't disconnect eDP */

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

@@ -1056,7 +1056,7 @@ intel_dp_mst_detect(struct drm_connector *connector,
 	struct intel_connector *intel_connector = to_intel_connector(connector);
 	struct intel_dp *intel_dp = intel_connector->mst_port;
 
-	if (!INTEL_DISPLAY_ENABLED(i915))
+	if (!intel_display_device_enabled(i915))
 		return connector_status_disconnected;
 
 	if (drm_connector_is_unregistered(connector))

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

@@ -319,7 +319,7 @@ intel_dvo_detect(struct drm_connector *_connector, bool force)
 	drm_dbg_kms(&i915->drm, "[CONNECTOR:%d:%s]\n",
 		    connector->base.base.id, connector->base.name);
 
-	if (!INTEL_DISPLAY_ENABLED(i915))
+	if (!intel_display_device_enabled(i915))
 		return connector_status_disconnected;
 
 	return intel_dvo->dev.dev_ops->detect(&intel_dvo->dev);

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

@@ -2496,7 +2496,7 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
 	drm_dbg_kms(&dev_priv->drm, "[CONNECTOR:%d:%s]\n",
 		    connector->base.id, connector->name);
 
-	if (!INTEL_DISPLAY_ENABLED(dev_priv))
+	if (!intel_display_device_enabled(dev_priv))
 		return connector_status_disconnected;
 
 	wakeref = intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS);

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

@@ -763,7 +763,7 @@ static void i915_hpd_poll_init_work(struct work_struct *work)
 void intel_hpd_poll_enable(struct drm_i915_private *dev_priv)
 {
 	if (!HAS_DISPLAY(dev_priv) ||
-	    !INTEL_DISPLAY_ENABLED(dev_priv))
+	    !intel_display_device_enabled(dev_priv))
 		return;
 
 	WRITE_ONCE(dev_priv->display.hotplug.poll_enabled, true);

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

@@ -680,7 +680,7 @@ intel_panel_detect(struct drm_connector *connector, bool force)
 {
 	struct drm_i915_private *i915 = to_i915(connector->dev);
 
-	if (!INTEL_DISPLAY_ENABLED(i915))
+	if (!intel_display_device_enabled(i915))
 		return connector_status_disconnected;
 
 	return connector_status_connected;

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

@@ -2121,7 +2121,7 @@ intel_sdvo_detect(struct drm_connector *connector, bool force)
 	DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n",
 		      connector->base.id, connector->name);
 
-	if (!INTEL_DISPLAY_ENABLED(i915))
+	if (!intel_display_device_enabled(i915))
 		return connector_status_disconnected;
 
 	if (!intel_sdvo_set_target_output(intel_sdvo,

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

@@ -1720,7 +1720,7 @@ intel_tv_detect(struct drm_connector *connector,
 	drm_dbg_kms(&i915->drm, "[CONNECTOR:%d:%s] force=%d\n",
 		    connector->base.id, connector->name, force);
 
-	if (!INTEL_DISPLAY_ENABLED(i915))
+	if (!intel_display_device_enabled(i915))
 		return connector_status_disconnected;
 
 	if (force) {

drivers/gpu/drm/i915/i915_drv.h

@@ -821,12 +821,6 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
 #define NUM_L3_SLICES(i915) (IS_HASWELL_GT3(i915) ? \
 				 2 : HAS_L3_DPF(i915))
 
-/* Only valid when HAS_DISPLAY() is true */
-#define INTEL_DISPLAY_ENABLED(i915) \
-	(drm_WARN_ON(&(i915)->drm, !HAS_DISPLAY(i915)),		\
-	 !(i915)->params.disable_display &&				\
-	 !intel_opregion_headless_sku(i915))
-
 #define HAS_GUC_DEPRIVILEGE(i915) \
 	(INTEL_INFO(i915)->has_guc_deprivilege)