[PATCH 10/12] drm/edid: add a helper to compare two EDIDs

[Thomas Weißschuh]

As struct drm_edid is opaque, drivers can't directly memcmp() the
contained data. Add a helper to provide this functionality.

Signed-off-by: Thomas Weißschuh <linux at weissschuh.net>
---
 drivers/gpu/drm/drm_edid.c | 18 ++++++++++++++++++
 include/drm/drm_edid.h     |  1 +
 2 files changed, 19 insertions(+)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 69fb11741abd..c2493c983a64 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1840,6 +1840,24 @@ static bool drm_edid_eq(const struct drm_edid *drm_edid,
 	return true;
 }
 
+/**
+ * drm_edid_equal - compare two EDID
+ * @drm_edid_a: First EDID data
+ * @drm_edid_b: Second EDID data
+ *
+ * Compare two EDIDs for equality (including extensions)
+ *
+ * Return: True if the EDIDs are equal, false otherwise.
+ */
+bool drm_edid_equal(const struct drm_edid *drm_edid_a, const struct drm_edid *drm_edid_b)
+{
+	if (!drm_edid_b)
+		return !drm_edid_a;
+
+	return drm_edid_eq(drm_edid_a, drm_edid_b->edid, drm_edid_b->size);
+}
+EXPORT_SYMBOL(drm_edid_equal);
+
 enum edid_block_status {
 	EDID_BLOCK_OK = 0,
 	EDID_BLOCK_READ_FAIL,
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index a5b377c4a342..35b40a9d3350 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -456,6 +456,7 @@ drm_display_mode_from_cea_vic(struct drm_device *dev,
 const struct drm_edid *drm_edid_alloc(const void *edid, size_t size);
 const struct drm_edid *drm_edid_dup(const struct drm_edid *drm_edid);
 void drm_edid_free(const struct drm_edid *drm_edid);
+bool drm_edid_equal(const struct drm_edid *drm_edid_a, const struct drm_edid *drm_edid_b);
 bool drm_edid_valid(const struct drm_edid *drm_edid);
 const struct edid *drm_edid_raw(const struct drm_edid *drm_edid);
 const struct drm_edid *drm_edid_read(struct drm_connector *connector);

-- 
2.46.0