Re: X modeline conversions
*- On 1 Jul, Matthew Gregan wrote about "X modeline conversions"
> Hi everyone.
>
> I'm trying to work out a good modeline for X for 1152x864. The reason I'm doing this is because I was installing some new drivers for my video card under Windows and discovered that my monitor can do 1152x864 at an acceptable refresh rate...
>
> I've got the figures from Windows, but I only vaguely understand how they relate to the X modelines, and I can't figure out how to convert them over. Hopefully someone with more experience can point me in the right direction...
>
> Under Windows, this is the info I have about the mode:
> Pixel clock: 112320kHz
>
> Horizontal:
> Frequency: 70kHz
> Front porch: 64 pixels
> Sync: 128 pixels
> Back porch: 256 pixels
> Negative sync polarity
>
> Vertical:
> Frequency: 78Hz
> Front porch: 1 line
> Sync: 3 lines
> Back porch: 2 lines
> Negative sync polarity
>
> I've tried reading through ESR's XF86 video timings howto, but it wasn't really helpful to my problem. From what I understand, the front/back porch is the time of the rise and fall of the signal, but I don't know how to relate the numbers I have back to anything useful for X.
>
> I've found a modeline already existing in the XF86 config which is very close to what I want (1152x864 at 78Hz, but it's 70.8kHz horizontal frequency is just too much for my monitor to handle).
>
> If anybody can help, or point me in the right direction, I would be very happy. Thanks. :-)
>
> Oh, those Windows figures are from the Matrox monitor customization utility, if that matters...
You can give Colas' XFree Modeline Generator at
http://www.inria.fr/cgi-bin/nph-colas-modelines a try. It will give you
a whole range of modelines. You could also us xvidtune to fine tune a
mode that is close to what you want.
--
Brian
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