2 files changed, 74 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index ecd6e9255b67..8fed2131f424 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -102,6 +102,11 @@ struct detailed_mode_closure {
 	int modes;
 };
 
+struct drm_edid_match_closure {
+	const struct drm_edid_ident *ident;
+	bool matched;
+};
+
 #define LEVEL_DMT	0
 #define LEVEL_GTF	1
 #define LEVEL_GTF2	2
@@ -5456,6 +5461,66 @@ drm_parse_hdmi_vsdb_audio(struct drm_connector *connector, const u8 *db)
 }
 
 static void
+match_identity(const struct detailed_timing *timing, void *data)
+{
+	struct drm_edid_match_closure *closure = data;
+	unsigned int i;
+	const char *name = closure->ident->name;
+	unsigned int name_len = strlen(name);
+	const char *desc = timing->data.other_data.data.str.str;
+	unsigned int desc_len = ARRAY_SIZE(timing->data.other_data.data.str.str);
+
+	if (name_len > desc_len ||
+	    !(is_display_descriptor(timing, EDID_DETAIL_MONITOR_NAME) ||
+	      is_display_descriptor(timing, EDID_DETAIL_MONITOR_STRING)))
+		return;
+
+	if (strncmp(name, desc, name_len))
+		return;
+
+	for (i = name_len; i < desc_len; i++) {
+		if (desc[i] == '\n')
+			break;
+		/* Allow white space before EDID string terminator. */
+		if (!isspace(desc[i]))
+			return;
+	}
+
+	closure->matched = true;
+}
+
+/**
+ * drm_edid_match - match drm_edid with given identity
+ * @drm_edid: EDID
+ * @ident: the EDID identity to match with
+ *
+ * Check if the EDID matches with the given identity.
+ *
+ * Return: True if the given identity matched with EDID, false otherwise.
+ */
+bool drm_edid_match(const struct drm_edid *drm_edid,
+		    const struct drm_edid_ident *ident)
+{
+	if (!drm_edid || drm_edid_get_panel_id(drm_edid) != ident->panel_id)
+		return false;
+
+	/* Match with name only if it's not NULL. */
+	if (ident->name) {
+		struct drm_edid_match_closure closure = {
+			.ident = ident,
+			.matched = false,
+		};
+
+		drm_for_each_detailed_block(drm_edid, match_identity, &closure);
+
+		return closure.matched;
+	}
+
+	return true;
+}
+EXPORT_SYMBOL(drm_edid_match);
+
+static void
 monitor_name(const struct detailed_timing *timing, void *data)
 {
 	const char **res = data;
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index 9686a7cee6a6..6f65bbf655a1 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -312,6 +312,13 @@ struct edid {
 	u8 checksum;
 } __packed;
 
+/* EDID matching */
+struct drm_edid_ident {
+	/* ID encoded by drm_edid_encode_panel_id() */
+	u32 panel_id;
+	const char *name;
+};
+
 #define EDID_PRODUCT_ID(e) ((e)->prod_code[0] | ((e)->prod_code[1] << 8))
 
 /* Short Audio Descriptor */
@@ -412,6 +419,8 @@ struct edid *drm_get_edid(struct drm_connector *connector,
 			  struct i2c_adapter *adapter);
 const struct drm_edid *drm_edid_read_base_block(struct i2c_adapter *adapter);
 u32 drm_edid_get_panel_id(const struct drm_edid *drm_edid);
+bool drm_edid_match(const struct drm_edid *drm_edid,
+		    const struct drm_edid_ident *ident);
 struct edid *drm_get_edid_switcheroo(struct drm_connector *connector,
 				     struct i2c_adapter *adapter);
 struct edid *drm_edid_duplicate(const struct edid *edid);