drm/edid: fix invalid EDID extension block filtering

From Jani Nikula
96db9afa4958bbaee77995eb0c84e08cdcce74ae in linux 5.15.y/5.15.46
3aefc722ff52076407203b6af9713de567993adf in mainline linux

diff --git a/sys/dev/pci/drm/drm_edid.c b/sys/dev/pci/drm/drm_edid.c
index 895587a..8f54eee 100644 (file)
--- a/sys/dev/pci/drm/drm_edid.c
+++ b/sys/dev/pci/drm/drm_edid.c
@@ -2002,9 +2002,6 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
 
                connector_bad_edid(connector, edid, edid[0x7e] + 1);
 
-               edid[EDID_LENGTH-1] += edid[0x7e] - valid_extensions;
-               edid[0x7e] = valid_extensions;
-
                new = kmalloc_array(valid_extensions + 1, EDID_LENGTH,
                                    GFP_KERNEL);
                if (!new)
@@ -2021,6 +2018,9 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
                        base += EDID_LENGTH;
                }
 
+               new[EDID_LENGTH - 1] += new[0x7e] - valid_extensions;
+               new[0x7e] = valid_extensions;
+
                kfree(edid);
                edid = new;
        }