[Bug Report] drm/edid: drm_edid_override_connector_update returns a incorrect value

[bbaa]

Hello everyone,

drm_edid_override_connector_update seem return a incorrect value.

drivers/gpu/drm/drm_edid.c (Linux 6.7-rc4)
  2294	/**
  2295	 * drm_edid_override_connector_update - add modes from override/firmware EDID
  2296	 * @connector: connector we're probing
  2297	 *
  2298	 * Add modes from the override/firmware EDID, if available. Only to be used from
  2299	 * drm_helper_probe_single_connector_modes() as a fallback for when DDC probe
  2300	 * failed during drm_get_edid() and caused the override/firmware EDID to be
  2301	 * skipped.
  2302	 *
  2303	 * Return: The number of modes added or 0 if we couldn't find any.
  2304	 */
  2305	int drm_edid_override_connector_update(struct drm_connector *connector)
  2306	{
  2307		const struct drm_edid *override;
  2308		int num_modes = 0;
  2309	
  2310		override = drm_edid_override_get(connector);
  2311		if (override) {
  2312			num_modes = drm_edid_connector_update(connector, override);
  2313	
  2314			drm_edid_free(override);
  2315	
  2316			drm_dbg_kms(connector->dev,
  2317				    "[CONNECTOR:%d:%s] adding %d modes via fallback override/firmware EDID\n",
  2318				    connector->base.id, connector->name, num_modes);
  2319		}
  2320	
  2321		return num_modes;
  2322	}
  2323	EXPORT_SYMBOL(drm_edid_override_connector_update);

The comment describes that it will return the number of modes added
However the function calls drm_edid_connector_update, will return 0 upon successful execution.

drivers/gpu/drm/drm_edid.c
  6813	/**
  6814	 * drm_edid_connector_update - Update connector information from EDID
  6815	 * @connector: Connector
  6816	 * @drm_edid: EDID
  6817	 *
  6818	 * Update the connector display info, ELD, HDR metadata, relevant properties,
  6819	 * etc. from the passed in EDID.
  6820	 *
  6821	 * If EDID is NULL, reset the information.
  6822	 *
  6823	 * Must be called before calling drm_edid_connector_add_modes().
  6824	 *
  6825	 * Return: 0 on success, negative error on errors.
  6826	 */
  6827	int drm_edid_connector_update(struct drm_connector *connector,
  6828				      const struct drm_edid *drm_edid)
  6829	{
  6830		update_display_info(connector, drm_edid);
  6831	
  6832		_drm_update_tile_info(connector, drm_edid);
  6833	
  6834		return _drm_edid_connector_property_update(connector, drm_edid);
  6835	}
  6836	EXPORT_SYMBOL(drm_edid_connector_update);

This will break the EDID override behavior on Nvidia graphics cards.

NVIDIA/open-gpu-kernel-modules:
kernel-open/nvidia-drm/nvidia-drm-connector.c:
  103  #if defined(NV_DRM_CONNECTOR_HAS_OVERRIDE_EDID)   104      if 
(connector->override_edid) {   105  #else   106      if 
(drm_edid_override_connector_update(connector) > 0) {   107  #endif 
  108          const struct drm_property_blob *edid = 
connector->edid_blob_ptr;   109 
drm_edid_override_connector_update(connector)  will return zero here.

regards,
bbaa