ACPI: property: Ignore bad graph port nodes on Dell XPS 9315

Some systems were shipped with both Windows and Linux camera descriptions.
In general, if Linux description exist, they will be used and Windows
description ignored.

In this case the Linux descriptions were buggy so use Windows definition
instead. This patch ignores the bad graph port nodes on Dell XPS 9315 and
there are likely other such systems, too. The corresponding information
has been added to ipu-bridge to cover the missing bits.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: Sakari Ailus

drivers/acpi/internal.h

@@ -301,5 +301,6 @@ void acpi_mipi_check_crs_csi2(acpi_handle handle);
 void acpi_mipi_scan_crs_csi2(void);
 void acpi_mipi_init_crs_csi2_swnodes(void);
 void acpi_mipi_crs_csi2_cleanup(void);
+bool acpi_graph_ignore_port(acpi_handle handle);
 
 #endif /* _ACPI_INTERNAL_H_ */

drivers/acpi/mipi-disco-img.c

@@ -19,6 +19,7 @@
  */
 
 #include <linux/acpi.h>
+#include <linux/dmi.h>
 #include <linux/limits.h>
 #include <linux/list.h>
 #include <linux/module.h>
@@ -723,3 +724,73 @@ void acpi_mipi_crs_csi2_cleanup(void)
 	list_for_each_entry_safe(csi2, csi2_tmp, &acpi_mipi_crs_csi2_list, entry)
 		acpi_mipi_del_crs_csi2(csi2);
 }
+
+static const struct dmi_system_id dmi_ignore_port_nodes[] = {
+	{
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+			DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "XPS 9315"),
+		},
+	},
+	{ 0 }
+};
+
+static const char *strnext(const char *s1, const char *s2)
+{
+	s1 = strstr(s1, s2);
+
+	if (!s1)
+		return NULL;
+
+	return s1 + strlen(s2);
+}
+
+/**
+ * acpi_graph_ignore_port - Tell whether a port node should be ignored
+ * @handle: The ACPI handle of the node (which may be a port node)
+ *
+ * Returns true if a port node should be ignored and the data to that should
+ * come from other sources instead (Windows ACPI definitions and
+ * ipu-bridge). This is currently used to ignore bad port nodes related to IPU6
+ * ("IPU?") and camera sensor devices ("LNK?") in certain Dell systems with
+ * Intel VSC.
+ */
+bool acpi_graph_ignore_port(acpi_handle handle)
+{
+	const char *path = NULL, *orig_path;
+	static bool dmi_tested, ignore_port;
+
+	if (!dmi_tested) {
+		ignore_port = dmi_first_match(dmi_ignore_port_nodes);
+		dmi_tested = true;
+	}
+
+	if (!ignore_port)
+		return false;
+
+	/* Check if the device is either "IPU" or "LNK" (sensor). */
+	orig_path = acpi_handle_path(handle);
+	if (!orig_path)
+		return false;
+	path = strnext(orig_path, "IPU");
+	if (!path)
+		path = strnext(orig_path, "LNK");
+	if (!path)
+		goto out_free;
+
+	if (!(path[0] >= '0' && path[0] <= '9' && path[1] == '.'))
+		goto out_free;
+
+	/* Check if the node has a "PRT" prefix. */
+	path = strnext(path, "PRT");
+	if (path && path[0] >= '0' && path[0] <= '9' && !path[1]) {
+		acpi_handle_debug(handle, "ignoring data node\n");
+
+		kfree(orig_path);
+		return true;
+	}
+
+out_free:
+	kfree(orig_path);
+	return false;
+}

drivers/acpi/property.c

@@ -80,6 +80,9 @@ static bool acpi_nondev_subnode_extract(union acpi_object *desc,
 	struct acpi_data_node *dn;
 	bool result;
 
+	if (acpi_graph_ignore_port(handle))
+		return false;
+
 	dn = kzalloc(sizeof(*dn), GFP_KERNEL);
 	if (!dn)
 		return false;