Can't change refresh rate (Deb3.1)

[Yauolf]

Hi,

I can't change the refresh rate with the "Desktop Preferences -> Screen Resolution" tool (Gnome). I may select a different resolution, but for each of those there's only one refresh rate (70/70/75 Hz, a torture for my eyes).

Kernel version is 2.6.

The /etc/X11/XF86Config-4 says at the "Monitor" section

HorizSync 30.0 - 60.0
VertRefresh 50.0 - 150.0

which should be sufficient for 100 Hz at 1024x768 and

Section "Screen"
Identifier "Default Screen"
Device "NVidia Ti4200"
Monitor "CTX 1792SE"
DefaultDepth 24
SubSection "Display"
Depth 1
Modes "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 4
Modes "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 8
Modes "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 15
Modes "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 16
Modes "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 24
Modes "1024x768" "800x600" "640x480"
EndSubSection
EndSection

Or maybe it has something to do with the nVidia-drivers? Unfortunately, I don't remember if I already had this problem before installing them...

Any help is appreciated.

[farslayer]

The GTF XFree86 modeline generator is a utility for calculating VESA GTF modes. Given the desired horizontal and vertical resolutions and refresh rate (in Hz), the parameters for a matching VESA GTF mode are printed out. Two output formats are supported: mode lines suitable for the XFree86 XF86Config(5x) file, and mode parameters suitable for the Linux fbset( utility.

This utility is already distributed with XFree86 4.3; if you have XFree86 4.3, then you probably already have gtf installed on your system (run `which gtf` to check).

itg-debian:~# gtf --help

usage: gtf x y refresh [-v|--verbose] [-f|--fbmode] [-x|-xf86mode]

            x : the desired horizontal resolution (required)
            y : the desired vertical resolution (required)
      refresh : the desired refresh rate (required)
 -v|--verbose : enable verbose printouts (traces each step of the computation)
  -f|--fbmode : output an fbset(8)-style mode description
 -x|-xf86mode : output an XFree86-style mode description (this is the default
                if no mode description is requested)

itg-debian:~# gtf 1024 768 100 -x

# 1024x768 @ 100.00 Hz (GTF) hsync: 81.40 kHz; pclk: 113.31 MHz
Modeline "1024x768_100.00" 113.31 1024 1096 1208 1392 768 769 772 814 -HSync +Vsync



use gtf to generate the modeline for your hardware as shown above, then Copy paste the new Modeline to Monitor section of your XF86Config-4 file. Watch that the hsync is in range with the HorizSync on the same section Also the VertRefresh and the refresh rate you selected should match

Restart X


As you can see from the modeline I generated above the 81.40 Khz for the horizontal sync is OUTSIDE the range you have defined for your monitors supported frequencies.. (30-60) which may be why your monitor won't go above 75 Hz.. you need to start by confirming your monitor specs for vert and horiz refresh..