[TRYBOT 06/10] drm/edid: add separate drm_edid_connector_add_modes()

[Jani Nikula]

The goal was to have a single drm_edid_connector_update() without a
separate call for adding modes, but that turned out to be problematic
for drivers that wish to have a connector update in the ->detect()
hook. Turns out ->detect() is called so many times that the probed mode
list fills up without bounds, in part because add_alternate_cea_modes()
duplicates modes.

Kudos to Imre Deak <imre.deak at intel.com> for explaining this to me.

Split out drm_edid_connector_add_modes() from
drm_edid_connector_update(). However, add the modes from the EDID
property that is expected to have been set by
drm_edid_connector_update() beforehands to enforce the order of the
function calls.

Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/drm_edid.c         | 39 +++++++++++++++++++++++-------
 drivers/gpu/drm/drm_probe_helper.c |  4 ++-
 include/drm/drm_edid.h             |  2 ++
 3 files changed, 35 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 2ac16b4dbb22..0277cf550ecd 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -6671,30 +6671,51 @@ static int _drm_edid_connector_property_update(struct drm_connector *connector,
  * @connector: Connector
  * @drm_edid: EDID
  *
- * Update the connector mode list, display info, ELD, HDR metadata, relevant
- * properties, etc. from the passed in EDID.
+ * Update the connector display info, ELD, HDR metadata, relevant properties,
+ * etc. from the passed in EDID.
  *
  * If EDID is NULL, reset the information.
  *
- * Return: The number of modes added or 0 if we couldn't find any.
+ * Must be called before drm_edid_connector_add_modes().
+ *
+ * Return: 0 on success, negative error on errors.
  */
 int drm_edid_connector_update(struct drm_connector *connector,
 			      const struct drm_edid *drm_edid)
 {
+	update_display_info(connector, drm_edid);
+
+	_drm_update_tile_info(connector, drm_edid);
+
+	return _drm_edid_connector_property_update(connector, drm_edid);
+}
+EXPORT_SYMBOL(drm_edid_connector_update);
+
+/**
+ * drm_edid_connector_add_modes - Update mode list from EDID
+ * @connector: Connector
+ *
+ * Update the connector mode list from the EDID previously updated with
+ * drm_edid_connector_update().
+ *
+ * Return: The number of modes added or 0 if we couldn't find any.
+ */
+int drm_edid_connector_add_modes(struct drm_connector *connector)
+{
+	const struct drm_edid *drm_edid = NULL;
 	int count;
 
-	update_display_info(connector, drm_edid);
+	if (connector->edid_blob_ptr)
+		drm_edid = drm_edid_alloc(connector->edid_blob_ptr->data,
+					  connector->edid_blob_ptr->length);
 
 	count = _drm_edid_connector_add_modes(connector, drm_edid);
 
-	_drm_update_tile_info(connector, drm_edid);
-
-	/* Note: Ignore errors for now. */
-	_drm_edid_connector_property_update(connector, drm_edid);
+	drm_edid_free(drm_edid);
 
 	return count;
 }
-EXPORT_SYMBOL(drm_edid_connector_update);
+EXPORT_SYMBOL(drm_edid_connector_add_modes);
 
 static int _drm_connector_update_edid_property(struct drm_connector *connector,
 					       const struct drm_edid *drm_edid)
diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index 1ea053cef557..26844befc6f5 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -1139,7 +1139,9 @@ int drm_connector_helper_get_modes(struct drm_connector *connector)
 	 * EDID. Otherwise, if the EDID is NULL, clear the connector
 	 * information.
 	 */
-	count = drm_edid_connector_update(connector, drm_edid);
+	drm_edid_connector_update(connector, drm_edid);
+
+	count = drm_edid_connector_add_modes(connector);
 
 	drm_edid_free(drm_edid);
 
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index 372963600f1d..70ae6c290bdc 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -609,6 +609,8 @@ const struct drm_edid *drm_edid_read_custom(struct drm_connector *connector,
 					    void *context);
 int drm_edid_connector_update(struct drm_connector *connector,
 			      const struct drm_edid *edid);
+int drm_edid_connector_add_modes(struct drm_connector *connector);
+
 const u8 *drm_find_edid_extension(const struct drm_edid *drm_edid,
 				  int ext_id, int *ext_index);
 
-- 
2.34.1