udldrmfb: Fix EDID not working with monitors with EDID extension blocks

[~andy/linux] / drivers / gpu / drm / udl / udl_connector.c

diff --git a/drivers/gpu/drm/udl/udl_connector.c b/drivers/gpu/drm/udl/udl_connector.c
index 512f44add89f41fae6706114c5ce497279a4f107..3e6208f773e28f434539dbfd4c3de0cb929c9e58 100644 (file)
--- a/drivers/gpu/drm/udl/udl_connector.c
+++ b/drivers/gpu/drm/udl/udl_connector.c
@@ -57,6 +57,14 @@ static int udl_get_modes(struct drm_connector *connector)
 
        edid = (struct edid *)udl_get_edid(udl);
 
+       /*
+        * We only read the main block, but if the monitor reports extension
+        * blocks then the drm edid code expects them to be present, so patch
+        * the extension count to 0.
+        */
+       edid->checksum += edid->extensions;
+       edid->extensions = 0;
+
        drm_mode_connector_update_edid_property(connector, edid);
        ret = drm_add_edid_modes(connector, edid);
        kfree(edid);