From a26865fcbabe066df57a248e2f7ed8403f60aef7 Mon Sep 17 00:00:00 2001
From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Date: Tue, 17 Aug 2021 23:51:58 +0200
Subject: drm/i915: Associate ACPI connector nodes with connector entries (v2)
Git-commit: a481d0e80eabbc3fed666103744aeaf47f63e708
Patch-mainline: v5.16-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

On Intel platforms we know that the ACPI connector device
node order will follow the order the driver (i915) decides.
The decision is made using the custom Intel ACPI OpRegion
(intel_opregion.c), though the driver does not actually know
that the values it sends to ACPI there are used for
associating a device node for the connectors, and assigning
address for them.

In reality that custom Intel ACPI OpRegion actually violates
ACPI specification (we supply dynamic information to objects
that are defined static, for example _ADR), however, it
makes assigning correct connector node for a connector entry
straightforward (it's one-on-one mapping).

Changes in v2 (Hans de goede):
- Take a reference on the fwnode which we assign to the connector,
  for ACPI nodes this is a no-op but in the future we may see
  software-fwnodes assigned to connectors which are ref-counted.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Tested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210817215201.795062-6-hdegoede@redhat.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/display/intel_acpi.c    | 46 ++++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_acpi.h    |  3 ++
 drivers/gpu/drm/i915/display/intel_display.c |  1 +
 3 files changed, 50 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_acpi.c b/drivers/gpu/drm/i915/display/intel_acpi.c
index 68abeaf2d7d4..e78430001f07 100644
--- a/drivers/gpu/drm/i915/display/intel_acpi.c
+++ b/drivers/gpu/drm/i915/display/intel_acpi.c
@@ -285,3 +285,49 @@ void intel_acpi_device_id_update(struct drm_i915_private *dev_priv)
 	}
 	drm_connector_list_iter_end(&conn_iter);
 }
+
+/* NOTE: The connector order must be final before this is called. */
+void intel_acpi_assign_connector_fwnodes(struct drm_i915_private *i915)
+{
+	struct drm_connector_list_iter conn_iter;
+	struct drm_device *drm_dev = &i915->drm;
+	struct fwnode_handle *fwnode = NULL;
+	struct drm_connector *connector;
+	struct acpi_device *adev;
+
+	drm_connector_list_iter_begin(drm_dev, &conn_iter);
+	drm_for_each_connector_iter(connector, &conn_iter) {
+		/* Always getting the next, even when the last was not used. */
+		fwnode = device_get_next_child_node(drm_dev->dev, fwnode);
+		if (!fwnode)
+			break;
+
+		switch (connector->connector_type) {
+		case DRM_MODE_CONNECTOR_LVDS:
+		case DRM_MODE_CONNECTOR_eDP:
+		case DRM_MODE_CONNECTOR_DSI:
+			/*
+			 * Integrated displays have a specific address 0x1f on
+			 * most Intel platforms, but not on all of them.
+			 */
+			adev = acpi_find_child_device(ACPI_COMPANION(drm_dev->dev),
+						      0x1f, 0);
+			if (adev) {
+				connector->fwnode =
+					fwnode_handle_get(acpi_fwnode_handle(adev));
+				break;
+			}
+			fallthrough;
+		default:
+			connector->fwnode = fwnode_handle_get(fwnode);
+			break;
+		}
+	}
+	drm_connector_list_iter_end(&conn_iter);
+	/*
+	 * device_get_next_child_node() takes a reference on the fwnode, if
+	 * we stopped iterating because we are out of connectors we need to
+	 * put this, otherwise fwnode is NULL and the put is a no-op.
+	 */
+	fwnode_handle_put(fwnode);
+}
diff --git a/drivers/gpu/drm/i915/display/intel_acpi.h b/drivers/gpu/drm/i915/display/intel_acpi.h
index 9f197401c313..4a760a2baed9 100644
--- a/drivers/gpu/drm/i915/display/intel_acpi.h
+++ b/drivers/gpu/drm/i915/display/intel_acpi.h
@@ -13,6 +13,7 @@ void intel_register_dsm_handler(void);
 void intel_unregister_dsm_handler(void);
 void intel_dsm_get_bios_data_funcs_supported(struct drm_i915_private *i915);
 void intel_acpi_device_id_update(struct drm_i915_private *i915);
+void intel_acpi_assign_connector_fwnodes(struct drm_i915_private *i915);
 #else
 static inline void intel_register_dsm_handler(void) { return; }
 static inline void intel_unregister_dsm_handler(void) { return; }
@@ -20,6 +21,8 @@ static inline
 void intel_dsm_get_bios_data_funcs_supported(struct drm_i915_private *i915) { return; }
 static inline
 void intel_acpi_device_id_update(struct drm_i915_private *i915) { return; }
+static inline
+void intel_acpi_assign_connector_fwnodes(struct drm_i915_private *i915) { return; }
 #endif /* CONFIG_ACPI */
 
 #endif /* __INTEL_ACPI_H__ */
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 5c4c2bc4d433..ad622d0f569b 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -11670,6 +11670,7 @@ int intel_modeset_init_nogem(struct drm_i915_private *i915)
 
 	drm_modeset_lock_all(dev);
 	intel_modeset_setup_hw_state(dev, dev->mode_config.acquire_ctx);
+	intel_acpi_assign_connector_fwnodes(i915);
 	drm_modeset_unlock_all(dev);
 
 	for_each_intel_crtc(dev, crtc) {
-- 
2.38.1