Here’s how I resolved the issue I had with Ubuntu not detecting the full 1680×1050 resolution of my Acer 2016W monitor. First, I obtained several numbers from ddcprobe by entering the following from the command line:
ddcprobe is a part of xresprobe package, which can be intalled either via Synaptic Package Manager or apt-get.
The command yielded the frequency settings for the monitor, which in my case were
Horizontal Sync (kHZ): 31-84
Vertical Sync (HZ) : 56-44
I then opened /etc/X11/xorg.conf:
sudo gedit /etc/X11/xorg.conf
added a new Monitor section following the existing Monitor section and used the values from ddcprobe:
Identifier "Acer AL2016W"
Then in Screen section I changed the line that reads
Monitor "Generic Monitor"
Monitor "Acer AL2016W"
Lastly, I changed Modes line in Display subsections for bit depth 15,16 and 24 to read
Modes "1680x1050" "1024x768" "800x600" "640x480"
This gave me full 1680×1050 resolution after I rebooted, and also listed all the other resolutions supported by the monitor. I wanted to include a screenshot but I discovered that I cannot take a screenshot with PrintScreen key with the options list in that drop-down box displayed. I had to use Gimp’s delayed screenshot function (File->Acquire->Screen Shot) to obtain the picture:
I am still connected with a VGA cable because DVI introduces a margin around the image.