I found the answered buried in [this post][1].  The new setpci command is

    sudo setpci -s 00:03.0 0x7b.b=19

btw, this setting isn't "sticky" and won't persist across reboots-- it has to be set upon each boot.


  [1]: http://ubuntuforums.org/showpost.php?p=7620648&postcount=2