Two more comments...
1) The newer version of the nvidia-bl ( 0.22~jaunty ) package that I had installed was from the mactel support PPA ( lp:~mactel-support ).
2) Since upgrading to this new version, my Acer 26" monitor ( connected via mini-port to HDMI ) no longer work. I'll enter a separate bug for this...
Two more comments...
1) The newer version of the nvidia-bl ( 0.22~jaunty ) package that I had installed was from the mactel support PPA ( lp:~mactel-support ).
2) Since upgrading to this new version, my Acer 26" monitor ( connected via mini-port to HDMI ) no longer work. I'll enter a separate bug for this...