XFree 4.2.1 + GF4 + refresh rates

[Guest arise]

Here we go...

 

My problem is that even if i run both XP and Linux @ 1280x1024 resolutions, the display in Linux is way smaller (not close to the edges) than in Windows. This has to do with the refresh rates, which i found out that XFree defaults to 85Hz (whereas in Windows i have 100Hz).

 

Any attempt to play with the monitor controls and change the image size (in linux) will destroy the Windows settings, and the desktop flows over the monitor edges.

 

I tried to play with xvidtune, but the most i could get was 88Hz using 1280x1024...

 

Question is: how can i get my monitor (Belinea 106080 19", 110KHz) to display 1280x1024 @ 100Hz in Linux, just like in Windows?

 

PS - I've been trying to get some answers since yesterday on IRC, etc..but to no avail :(

 

PS - I found a good link for modeline generation: http://xtiming.sourceforge.net/cgi-bin/xtiming.pl, can anyone test it or know it already? I cannot try it myself until later on today...

[Guest ndeb]

I tried to play with xvidtune, but the most i could get was 88Hz using 1280x1024.

What ranges are u using in the Monitor section of /etc/X11/XF86Config-4 ? The two parameters in question are HorizSync and VertRefresh.

Make sure u have ranges that are large enough:

HorizSync    30-110

VertRefresh  50-110

Obviously, if VertRefresh has an upper limit less than 100Hz, X will not give you 100Hz.

[Guest arise]

Ranges for my monitor are:

 

30-110 and 50-160khz

[Guest ndeb]

Its possible that the horizontal frequency is not high enough. Can u try 50-200 kHz ?

[Guest anon]

My two pennies worth, My NEC Multisync LCD has the same problem you have until I rebuild the drivers, then its OK.

[Guest ndeb]

arise,

Are u using the nvidia binary drivers ? If yes, then rebuild them from the source rpm (as suggested by anon) and reinstall them. If that does not solve the problem, follow this portion from the README for nvidia drivers:

Option "UseEdidFreqs" "boolean"

 

               This option causes the X server to use the HorizSync

               and VertRefresh ranges given in a display device's EDID,

               if any.  EDID provided range information will override

               the HorizSync and VertRefresh ranges specified in the

               Monitor section.  If a display device does not provide an

               EDID, or the EDID doesn't specify an hsync or vrefresh

               range, then the X server will default to the HorizSync

               and VertRefresh ranges specified in the Monitor section.

[aRTee]

Xvidtune will not let you really change the frequency much, it's more for correct placement (width and height/position); you can't change the pixel clock in it.

 

But start xvidtune anyway (I was playing with it last evening myself), and copy the numbers to a file (for the horizontal stuff it's on the left side: 1280 1322 1328 1460 for instance; don't use these numbers, I'm just making them up, am not at my machine; for the vertical it's on the right side: 1024 1025 1028 1034; well, 4 numbers anyway) and don't forget to include the pixel clock.

You don't really have to copy these numbers, but just putting any number is not so unproblematic; I have the same vidcard and also closed source drivers, and they insist they want certain factors/differences to be a multiple of 4 etcetc.

 

Now for some magic: just make a modeline out of your numbers, and change the pixel clock by multiplying with 100/85.

 

In all the above: at your own risk, make sure you're not pushing your system too far. (I'm not just talking to the topicstarter, he knows his monitor can do it, since it does in win).

 

I have used the mentioned link for modelines, it works fine;

if it doesn't, just check in the file: /var/log/XF86.0.log (or something),

somewhere the report will tell you which modes are being used, and at what frequency the display is.

 

So first get your screen to (about) 100 Hz, then play with xvidtune to get to the right size, then adjust the pixel clock (in the modeline) to get exactly 100Hz.

 

BTW you do know how to start extra X-sessions, right?

From the console (ctrl-alt-F1)

 

X -xfconfig XF86Config-4.test :1 &

 

will start X without any window/desktopmanager on display 1 (ctrl-alt-F8)

ctrl-alt-F1 to go back to console,

 

export DISPLAY=:1

twm &

 

(you can start any desktopmanager you like, but if you have kde running on the first X, you may not want to run it on the second to avoid conflicts; or maybe it's not a problem; but anyway, running something nice and light is much nicer, since you're just testing anyway).

 

Then with ctrl-alt-F8 you go to the test X, and right click, start a terminal and fire up xvidtune.

Note that you can make a whole array of modelines for the same resolution:

 

modeline "1280x1024@85" [pixelclock] [bunch of numbers for timing]

modeline "1280x1024@100" [pixelclock] [bunch of numbers for timing]

etc.

 

Just make sure in the last monitor part, where you indicate the resolutions, to include them:

 

"1280x1024" "1280x1024@85" "1280x1024@100" "1152x864" "1024x768"

etc.

 

Then in X switch through these with ctrl-alt-+ or -

 

Kill the X server with ctrl-alt-backspace when you're done/happy, then copy the xfconfig file to the default location so it's used when X gets started, make sure your desired modeline is the first in line to be picked or the only one and restart your original x-session,.. done.

[Guest arise]

Ok, so the modelines generated by that website did not really work, most likely because i didn't edit XFConfig-4 correctly :)

 

Just to get things straight, what do i have to edit/insert and where?

 

ModeLine "1280x1024@100" 244.64 1280 1312 2240 2272 1024 1041 1058 1076 (has to go in the Monitor section?)

 

"1280x1024@100" has to go in the Screen section, along with the other resolutions for a given colour depth?

 

Is this right?