Force X.org to use a higher resolution

Q I want to access a computer, running without a monitor, via remote desktop connection (krdc). Because the remote machine boots without a monitor, X.org drops back to VGA (640x480). Is there any way I can force X.org to use a higher resolution? I do not want to use X forwarding, I need to view the whole desktop. The computer is running Debian Etch and I have attached my xorg.conf.

A This drop in resolution is caused by your X.org configuration. Here is the offending part of your xorg.conf:

Section "Monitor"
Identifier "BenQ T701"
Option      "DPMS"
EndSection

As you can see, once this part is extracted from the whole file, it gives no details about the monitor's capabilities and limitations. This is becoming a standard approach and generally works well with modern monitors that support EDID (Extended Display Identification Data). This is where the software queries the monitor and gets back the information needed to set up a suitable display. Since it is possible to damage a monitor by sending it a signal at too high a frequency or resolution - although most monitors have protection against that sort of thing these days - X.org falls back to a safe 640x480x8-bit display if it gets no response to its EDID query.

The solution is quite simple, add the information on horizontal and vertical frequencies that X.org needs, and it will stop trying to ask the nonexistent monitor. You need to add HorizSync and VertRefresh options to the Monitor section above. If you ever connect a monitor to that computer, you will find the values in the monitor's manual. If you are never, ever going to connect a monitor to this system, you can use any reasonable figures, otherwise get them from the monitor's manual to make sure it works when you to want to use it. After restarting X, you should find it opens a display at the resolution given in xorg.conf, 1,280x1,024.

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