can't set 60hz v refresh rate

[David Becker]

sean wrote:
> On fc4, updated, I have a dell flat screen with a intel i915g chips -
> using xoreg i820 - that I want to run at 1280x1024x60.
> 
> Desktop-> Preferences -> Screen Resoltuion does not let me change the
> refresh rate. It stays at 75hz.
> 
> I hand edited xorg.conf so that the monitor section has
> 
> VertRefresh   60

It's best to leave these values at whatever your monitor specifies.

If X doesn't automatically choose a suitable modeline for your monitor
(I assume you have some kind of TFT that doesn't work above 60 hz), then
you can calculate these values yourself;

Find a modeline calculator on the net. Given your monitor's
characteristics, they allow you to fix one or more parameters (such as
Vertical refresh rate and resolution) while finding the modeline values
to accommodate.

Copy the result of the modeline calculator to the 'Monitor' section of
xorg.conf.

I for instance used this to calculate a suitable interlaced
(exaggerated) 200Hz frequency for PAL television viewing as in:

Section "Monitor"
        Identifier   "LG915FTPlus"
        VendorName   "LG"
        ModelName    "915FTPlus"
        HorizSync    30.0 - 107.0
        VertRefresh  50.0 - 200.0
        Option      "dpms"
# TV (PAL) Viewing
# Measured xawtv dimensions at 760x573
# 200hz
        Modeline "760x573 at 200i" 64.46 760 792 1032 1064 573 582 593 603
interlace
EndSection

Then insert or append the modeline identifier ("760x573 at 200i") to the
list of Modes in the 'Screen' section of xorg.conf.

Regards,

	David