[PATCH 11/13] drm/edid: introduce a helper that compares edid data from two drm_edid

[Melissa Wen]

AMD driver has a function used to compare if two edid are the same; this
is useful to some of the link detection algorithms implemented by
amdgpu. Since the amdgpu function can be helpful for other drivers, this
commit abstracts the AMD function to make it available at the DRM level
by wrapping existent drm_edid_eq().

Co-developed-by: Rodrigo Siqueira <siqueira at igalia.com>
Signed-off-by: Rodrigo Siqueira <siqueira at igalia.com>
Signed-off-by: Melissa Wen <mwen at igalia.com>
---
 drivers/gpu/drm/drm_edid.c | 18 ++++++++++++++++++
 include/drm/drm_edid.h     |  2 ++
 2 files changed, 20 insertions(+)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 855beafb76ff..328a25d198e5 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -7502,3 +7502,21 @@ bool drm_edid_is_digital(const struct drm_edid *drm_edid)
 		drm_edid->edid->input & DRM_EDID_INPUT_DIGITAL;
 }
 EXPORT_SYMBOL(drm_edid_is_digital);
+
+/**
+ * drm_edid_is_edid_eq - Check if it the EDID is equal
+ *
+ * @drm_edid_old: old drm_edid to compare edid
+ * @drm_edid_new: new drm_edid to compare edid
+ *
+ * Return true if the EDID is equal
+ */
+bool drm_edid_is_edid_eq(const struct drm_edid *drm_edid_old,
+			 const struct drm_edid *drm_edid_new)
+{
+	const void *old_edid = drm_edid_old->edid;
+	size_t old_edid_size = drm_edid_old->size;
+
+	return drm_edid_eq(drm_edid_new, old_edid, old_edid_size);
+}
+EXPORT_SYMBOL(drm_edid_is_edid_eq);
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index eaac5e665892..0e062761296c 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -469,6 +469,8 @@ int drm_edid_connector_update(struct drm_connector *connector,
 			      const struct drm_edid *edid);
 int drm_edid_connector_add_modes(struct drm_connector *connector);
 bool drm_edid_is_digital(const struct drm_edid *drm_edid);
+bool drm_edid_is_edid_eq(const struct drm_edid *drm_edid_first,
+			 const struct drm_edid *drm_edid_second);
 void drm_edid_get_product_id(const struct drm_edid *drm_edid,
 			     struct drm_edid_product_id *id);
 void drm_edid_print_product_id(struct drm_printer *p,
-- 
2.47.2