drm: read EDID extensions from monitor

Usually drm read basic EDID, that is enough for us, but since igital display
were introduced i.e. HDMI monitor, sometime we need to interact with monitor by
EDID extension information,

EDID extensions include audio/video data block, speaker allocation and vendor specific data blocks.

This patch intends to read EDID extensions from digital monitor for users.

Signed-off-by: Ma Ling <ling.ma@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 33ae98ce..9022b24 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -613,7 +613,8 @@
 extern int drm_mode_group_init_legacy_group(struct drm_device *dev, struct drm_mode_group *group);
 extern struct edid *drm_get_edid(struct drm_connector *connector,
 				 struct i2c_adapter *adapter);
-extern unsigned char *drm_do_probe_ddc_edid(struct i2c_adapter *adapter);
+extern int drm_do_probe_ddc_edid(struct i2c_adapter *adapter,
+				 unsigned char *buf, int len);
 extern int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid);
 extern void drm_mode_probed_add(struct drm_connector *connector, struct drm_display_mode *mode);
 extern void drm_mode_remove(struct drm_connector *connector, struct drm_display_mode *mode);