Comment 2 for bug 947544

StacktraceTop:
 brw_update_renderbuffer_surface (brw=0x7f9cbfe23040, rb=0x1edf420, unit=0) at brw_wm_surface_state.c:919
 brw_update_renderbuffer_surfaces (brw=0x7f9cbfe23040) at brw_wm_surface_state.c:1016
 brw_upload_state (brw=0x7f9cbfe23040) at brw_state_upload.c:503
 brw_try_draw_prims (max_index=<optimized out>, min_index=<optimized out>, ib=0x0, nr_prims=1, prim=0x7fff4a25eab0, arrays=0x1f48d48, ctx=0x7f9cbfe23040) at brw_draw.c:482
 brw_draw_prims (ctx=0x7f9cbfe23040, arrays=0x1f48d48, prim=0x7fff4a25eab0, nr_prims=1, ib=0x0, index_bounds_valid=<optimized out>, min_index=0, max_index=15, tfb_vertcount=0x0) at brw_draw.c:566