Comment 20 for bug 5264

I've found the following piece of information here:
http://wiki.cchtml.com/index.php/Ubuntu_Dapper_Installation_Guide

P zt3000 / Compaq nx7000

Beginning with ATI driver version 8.19, the drivers fail to properly detect modelines that are compatible with the LCD screen of the HP zt3000 (and equivalent Compaq nx7000 model), and they must be inserted into xorg.conf manually. For the 1680x1050 LCD screen, inserting the following modelines into the "Monitor" section works:

       Modeline "640x350" 119.12 640 1728 1760 1840 350 1052 1058 1080
       Modeline "640x400" 119.12 640 1728 1760 1840 400 1052 1058 1080
       Modeline "720x400" 119.12 720 1728 1760 1840 400 1052 1058 1080
       Modeline "640x480" 119.12 640 1728 1760 1840 480 1052 1058 1080
       Modeline "800x600" 119.12 800 1728 1760 1840 600 1052 1058 1080
       Modeline "1024x768" 119.12 1024 1728 1760 1840 768 1052 1058 1080
       Modeline "1152x864" 119.12 1152 1728 1760 1840 864 1052 1058 1080
       Modeline "1280x960" 119.12 1280 1728 1760 1840 960 1052 1058 1080
       Modeline "1280x1024" 119.12 1280 1728 1760 1840 1024 1052 1058 1080
       Modeline "832x624" 119.12 832 1728 1760 1840 624 1052 1058 1080
       Modeline "1280x768" 119.12 1280 1728 1760 1840 768 1052 1058 1080
       Modeline "1280x800" 119.12 1280 1728 1760 1840 800 1052 1058 1080
       Modeline "1152x768" 119.12 1152 1728 1760 1840 768 1052 1058 1080
       Modeline "1400x1050" 119.12 1400 1728 1760 1840 1050 1052 1058 1080
       Modeline "1440x900" 119.12 1440 1728 1760 1840 900 1052 1058 1080
       Modeline "1600x1024" 119.12 1600 1728 1760 1840 1024 1052 1058 1080
       Modeline "1680x1050" 119.12 1680 1728 1760 1840 1050 1052 1058 1080

If you have the "1920x1200" version of the HP zt3000 the Modeline is:

       Modeline "1920x1200" 150.75 1920 2016 2048 2185 1200 1202 1208 1235
I've tried it using my machine, and it didn't work (maybe because i've only added the
last line. i've got limited time to test it, sorry.

can any of you confirm whether it works or not?