Comment # 6 on bug 104490 from Mike Lothian

I think this also affects i965 too

6ce9006d76c050663af0be61cc88c3215d6f8cea is the first bad commit                
commit 6ce9006d76c050663af0be61cc88c3215d6f8cea                                 
Author: Neil Roberts <neil@linux.intel.com>                                     
Date:   Wed Oct 1 20:00:50 2014 +0100                                           

    i965: Enable flush control                                                  

    Reviewed-by: Adam Jackson <ajax@redhat.com>                                 
    Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>                       
    Reviewed-by: Emil Velikov <emil.velikov@collabora.com>                      
    Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>                        
    Signed-off-by: Neil Roberts <neil@linux.intel.com>