drm/i915: introduce INTEL_DISPLAY_ENABLED()

Prepare for making a distinction between not having display and having
disabled display. Add INTEL_DISPLAY_ENABLED() and use it where
HAS_DISPLAY() is used after intel_device_info_runtime_init(). This is
initially duplication, as disabling display still leads to ->pipe_mask =
0 and HAS_DISPLAY() being false.

Note that ever since i915.display_disable was introduced, it has not
affected PCH detection even if it uses HAS_DISPLAY(), as display disable
happens after that.

Since INTEL_DISPLAY_ENABLED() will not make sense unless HAS_DISPLAY()
is true, include a warning for catching misuses making decisions on
INTEL_DISPLAY_ENABLED() when HAS_DISPLAY() is false.

v2: Remove INTEL_DISPLAY_ENABLED() check from intel_detect_pch() (Chris)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190913100407.30991-1-jani.nikula@intel.com

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

@@ -1833,7 +1833,7 @@ void intel_bios_init(struct drm_i915_private *dev_priv)
 	const struct bdb_header *bdb;
 	u8 __iomem *bios = NULL;
 
-	if (!HAS_DISPLAY(dev_priv)) {
+	if (!HAS_DISPLAY(dev_priv) || !INTEL_DISPLAY_ENABLED(dev_priv)) {
 		DRM_DEBUG_KMS("Skipping VBT init due to disabled display.\n");
 		return;
 	}

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

@@ -15381,7 +15381,7 @@ static void intel_setup_outputs(struct drm_i915_private *dev_priv)
 
 	intel_pps_init(dev_priv);
 
-	if (!HAS_DISPLAY(dev_priv))
+	if (!HAS_DISPLAY(dev_priv) || !INTEL_DISPLAY_ENABLED(dev_priv))
 		return;
 
 	if (INTEL_GEN(dev_priv) >= 12) {
@@ -17293,7 +17293,7 @@ intel_display_capture_error_state(struct drm_i915_private *dev_priv)
 
 	BUILD_BUG_ON(ARRAY_SIZE(transcoders) != ARRAY_SIZE(error->transcoder));
 
-	if (!HAS_DISPLAY(dev_priv))
+	if (!HAS_DISPLAY(dev_priv) || !INTEL_DISPLAY_ENABLED(dev_priv))
 		return NULL;
 
 	error = kzalloc(sizeof(*error), GFP_ATOMIC);

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

@@ -444,7 +444,7 @@ int intel_fbdev_init(struct drm_device *dev)
 	struct intel_fbdev *ifbdev;
 	int ret;
 
-	if (WARN_ON(!HAS_DISPLAY(dev_priv)))
+	if (WARN_ON(!HAS_DISPLAY(dev_priv) || !INTEL_DISPLAY_ENABLED(dev_priv)))
 		return -ENODEV;
 
 	ifbdev = kzalloc(sizeof(struct intel_fbdev), GFP_KERNEL);

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

@@ -836,7 +836,7 @@ int intel_gmbus_setup(struct drm_i915_private *dev_priv)
 	unsigned int pin;
 	int ret;
 
-	if (!HAS_DISPLAY(dev_priv))
+	if (!HAS_DISPLAY(dev_priv) || !INTEL_DISPLAY_ENABLED(dev_priv))
 		return 0;
 
 	if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))

drivers/gpu/drm/i915/i915_drv.c

@@ -338,7 +338,7 @@ static int i915_driver_modeset_probe(struct drm_device *dev)
 	if (i915_inject_probe_failure(dev_priv))
 		return -ENODEV;
 
-	if (HAS_DISPLAY(dev_priv)) {
+	if (HAS_DISPLAY(dev_priv) && INTEL_DISPLAY_ENABLED(dev_priv)) {
 		ret = drm_vblank_init(&dev_priv->drm,
 				      INTEL_NUM_PIPES(dev_priv));
 		if (ret)
@@ -389,7 +389,7 @@ static int i915_driver_modeset_probe(struct drm_device *dev)
 
 	intel_overlay_setup(dev_priv);
 
-	if (!HAS_DISPLAY(dev_priv))
+	if (!HAS_DISPLAY(dev_priv) || !INTEL_DISPLAY_ENABLED(dev_priv))
 		return 0;
 
 	ret = intel_fbdev_init(dev);
@@ -1415,7 +1415,7 @@ static void i915_driver_register(struct drm_i915_private *dev_priv)
 	} else
 		DRM_ERROR("Failed to register driver for userspace access!\n");
 
-	if (HAS_DISPLAY(dev_priv)) {
+	if (HAS_DISPLAY(dev_priv) && INTEL_DISPLAY_ENABLED(dev_priv)) {
 		/* Must be done after probing outputs */
 		intel_opregion_register(dev_priv);
 		acpi_video_register();
@@ -1438,7 +1438,7 @@ static void i915_driver_register(struct drm_i915_private *dev_priv)
 	 * We need to coordinate the hotplugs with the asynchronous fbdev
 	 * configuration, for which we use the fbdev->async_cookie.
 	 */
-	if (HAS_DISPLAY(dev_priv))
+	if (HAS_DISPLAY(dev_priv) && INTEL_DISPLAY_ENABLED(dev_priv))
 		drm_kms_helper_poll_init(dev);
 
 	intel_power_domains_enable(dev_priv);

drivers/gpu/drm/i915/i915_drv.h

@@ -2192,6 +2192,9 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
 
 #define HAS_DISPLAY(dev_priv) (INTEL_INFO(dev_priv)->pipe_mask != 0)
 
+/* Only valid when HAS_DISPLAY() is true */
+#define INTEL_DISPLAY_ENABLED(dev_priv) (WARN_ON(!HAS_DISPLAY(dev_priv)), !i915_modparams.disable_display)
+
 static inline bool intel_vtd_active(void)
 {
 #ifdef CONFIG_INTEL_IOMMU