flickering screen = head ache

[Spazegun2213]

Hey all,
I would like to know how to change the refresh rate for my monitor. its not setup in Xconfigurator (or at least it didnt give ME that option). The screen flickers and i think(had problems with it in windows to) its the refresh rate.

Thanks

[mdwatts]

You will need to know your monitor/video card refresh rates etc. and then use either xf86config or xf86cfg (X4).

You can try to manually edit /etc/X11/XF86Config (-4) and change the refresh rate yourself, but make sure you know what you are doing, have the specs and most of all... be careful.

[Lorithar]

1) I'm basing this on XF86x 4.0.x ..

If you look in your X output log (/var/log XF86Config.0.log), there will be a line telling you what mode, including refresh rate the monitor and card combination chose .. ..

You might want to look farther back in that same log to see if perhaps there was a better mode to choose from.. or if the mode that you would prefer was skipped.... if it was skipped, the reason why is printed there as well.

If your mode was autoconfigured, there are likely excellent mathematical reasons why ... you play with modelines at *very* great risk of damaging your monitor...

Before proceeding, (I repeat the above advice) make *very* sure of what you do .. you can kill a monitor in as little as an instant in the wrong mode.

examples from my log
(--) R128(0): Virtual size is 1280x1024 (pitch 1280)
(**) R128(0): Default mode "1280x1024": 108.0 MHz, 64.0 kHz, 60.0 Hz
(II) R128(0): Modeline "1280x1024" 108.00 1280 1328 1440 1688 1024 1025 1028 1066 +hsync +vsync

and ..
(II) R128(0): Not using default mode "1600x1200" (hsync out of range)


Modelines pass the entire graphic card to monitor setup detail in one shot .. and are rather hard to understand... but there are hints out there that will give you more detail. (google XF86 Modelines)

You could post your graphics card and monitor specs that you know...

[stingray72]

I'm having the same problems... I looked up my monitor settings on the net.

----------------------------------
Specifications of eView 17p


Light Gray
OSD (On-Screen Display)
21"w x 18"h x 22"d
0.27mm
Non-glare, Plug & Play, Energy Star compliant
1280 x 1024 @ 60 Hz
17 inches
16" viewable
30~70 KHz (horizontal)
50~160 Hz (vertical)
AC 110~240V 60/50 Hz
16 inches
42 lbs.

------------------------------

I manually set the rates according to the specs above but my monitor is still flickering?

I don't know what to change. IT's not near another monitor or another power source or anything like that. It also flickers when I boot into windows.

Could a video card going bad cause this also?

[Spazegun2213]

well, i just got back from my trip and have not booted into linux yet :( but i can say that the refresh rate for this monitor in windows MUST be manually set to 60 Hertz or it will flicker.... so I'll try that in Linux.... now... i just need to figure out which property is refresh rate.... any suggestions?

thanks

[mdwatts]

Section "Monitor"
Identifier "Generic Monitor"
VendorName "Compaq"
ModelName "P2200"
HorizSync 30-121
VertRefresh 50-160
ModeLine "1800x1440/70Hz" 250 1800 1896 2088 2392 1440 1441 1444 1490 +HSync +VSync
ModeLine "640x480" 25.175 640 664 760 800 480 491 493 525
EndSection


Section "Screen"
Identifier "Screen0"
Device "Card0"
Monitor "Generic Monitor"
DefaultDepth 16
Subsection "Display"
Depth 32
Modes "1800x1440/70Hz" "640x480"
Virtual 0 0
EndSubsection

[Spazegun2213]

Watts, where did you find that info??
what config file??

thanks

[mdwatts]

The XFree86 config file...

/etc/X11/XF86Config-4 or XF86Config

[Spazegun2213]

well... i think i found the solution.... RH 7.3

I guess they changed/updated the X driver because now the screen no longer flickers and It has not shut off in about 1.5 hours. I really need to find out what they did to X so i can figure out what was REALLY going on.

Thanks to all who helped... I learned a lot about the X configuration :)

Thanks

[Spazegun2213]

ok... just for giggles... where would i find my refresh rate? i cant seem to pick it out of this file. could someone give me an idae of what to look for?

thanks

[DMR]

Originally posted by Spazegun2213:
<STRONG>...i cant seem to pick it out of this file. could someone give me an idae of what to look for?</STRONG>Your XF86Config-4 might not show you the specific refresh rate. If you look through /var/log/XFree86.0.log, you should find a lines similar to:
Default mode "1024x768": 94.5 MHz, 68.7 kHz, 85.0 Hz
which will tell you the settings used for a given resolution. Your distro might also have "xvidtune", which is a handy little program for detemining (and tweeking) your video settings. Use it with care though- it offers you a very friendly, graphical way of totally hosing your monitor.

:D

[ 13 May 2002: Message edited by: DMR ]

[Spazegun2213]

ok... the xvidtune shows what the refresh rate is, and i can see where that is in the XF86config as well. should i edit it there? How can i be ABSOLUTLY sure that the refresh rate i change in the XF86Config is the one that I'm useing?

Thanks