Re: Undefined video mode number: 314

[Stephen Powell <zlinuxman@wowway.com>]

On 2010-01-11 at 15:52:56 -0500, Stanisław T. Findeisen wrote:
> I tried "VertRefresh 85" because I know this monitor can handle 1024x768
> @ 85 Hz (well, at least it used to several years ago). Unfortunately the
> error I am getting now is: "vrefresh out of range" and I am only able to
> run X at:
> 
> 720x400x16 @ 85Hz, or
> 800x600x16 @ 60Hz

Well, we're making progress.  Your monitor apparently does not support
DDC2/EDID; so the X server does not know what your monitor's horizontal
and vertical sync frequency ranges are.  You have to tell it.  The "safe"
assumptions that the X server is making are well below your monitor's
capabilities.

You probably don't need to compose your own modeline though.  Let's see.
You told me that your monitor is a Samsung SyncMaster 550b.  According to
the owner's manual, which I found on the Internet, the horizontal sync
frequency range is 30 kHz to 70 kHz, and the vertical sync frequency range
is 50 Hz to 160 Hz.  The video bandwidth (maximum pixel clock) is 110 MHz.
That's less than the maximum pixel clock rate supported by the video card;
so you should be OK there, as we can see from

> (--) s3(0): Max pixel clock at this depth is 80 Mhz

So your monitor section (you should have only one monitor section)
should look something like this:

Section "Monitor"
	Identifier      "Configured Monitor"
	VendorName      "Samsung"
	ModelName       "SyncMaster 550b"
        HorizSync       30-70
        VertRefresh     50-160
        Option          "TargetRefresh"        "75"
EndSection
     
The "TargetRefresh" option is optional.  If used, it will try to use only
video modes of 75 Hz vertical sync or higher.  Give that a whirl and see
what happens.  Make sure that you are specifying the color depth as 16
(DefaultDepth 16 in the "Screen" section).