commit c9126d66fa8e535a53d45adda44c3275fa2e229f
Author: Brian Paul <brianp@vmware.com>
Date:   Thu Nov 11 07:43:30 2010 -0700

    mesa: improve error message

diff --git a/src/mesa/main/formats.c b/src/mesa/main/formats.c
index e18a9fc..46a1fe0 100644
--- a/src/mesa/main/formats.c
+++ b/src/mesa/main/formats.c
@@ -1428,7 +1428,8 @@ _mesa_format_to_type_and_comps(gl_format format,
 
 
    default:
-      _mesa_problem(NULL, "bad format in _mesa_format_to_type_and_comps");
+      _mesa_problem(NULL, "bad format %s in _mesa_format_to_type_and_comps",
+                    _mesa_get_format_name(format));
       *datatype = 0;
       *comps = 1;
    }