Stuart Sears wrote:
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sean enlightened us with the following gems on 15/10/05 18:34:
David Becker wrote:
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@200i" 64.46 760 792 1032 1064 573 582 593 603
interlace
EndSection
Then insert or append the modeline identifier ("760x573@200i") to the
list of Modes in the 'Screen' section of xorg.conf.
Regards,
David
Great idea. I'll try it.
sean
there is a built-in Modeline calculator on your system, called gtf
syntax (for 1024x768@ 60Hz):
gtf 1024 768 60
should generate output a bit like
# 1024x768 @ 60.00 Hz (GTF) hsync: 47.70 kHz; pclk: 64.11 MHz
Modeline "1024x768_60.00" 64.11 1024 1080 1184 1344 768 769 772 795
-HSync +Vsync
you can drop the -HSync +Vsync bit, and this would give you a modeline
(in your Monitor section of xorg.conf)...
Modeline "1024x768" 64.11 1024 1080 1184 1344 768 769 772 795
I used to have to do this for my Dell widescreen laptop.
Regards
Stuart
This seemed like a much better idea before I started poking
arooung. I used gtf and four web based modeline calculators.
They each gave a different result!!
Is this engineering or mysticism?
gtf 1280 1024 60
# 1280x1024 @ 60.00 Hz (GTF) hsync: 63.60 kHz; pclk:
108.88 MHz
Modeline "1280x1024_60.00" 108.88 1280 1360 1496 1712
1024 1025 1028 1060 -HSync +Vsync
http://www.dkfz-heidelberg.de/spec/linux/modeline/
Horizontal Resolution: 1280
Vertical Resolution: 1024
Vertical Refresh Rate: 60.00 Hz
Horizontal Refresh Rate: 63.73 KHz
Dot Clock Frequence: 109.62 MHz
# V-freq: 60.00 Hz // h-freq: 63.73 KHz
Modeline "1280x1024" 109.62 1280 1336 1472 1720 1024 1024
1026 1062
http://xtiming.sourceforge.net/cgi-bin/xtiming.pl
XFree86 Modeline
Put the following modeline in your XF86Config in the
Monitors section, and add it to your active modes in the
Screen section. Use this modeline at your own risk.
Modeline "1280x1024@60" 114.98 1280 1312 1744 1776 1024 1045
1055 1076
Horizontal sync frequency: 64.73 kHz
http://koala.ilog.fr/cgi-bin/nph-colas-modelines
Colas XFree Modeline Generator results
Computed by http://koala.ilog.fr/cgi-bin/nph-colas-modelines
Max Bandwidth: 200 Mhz
Max Vertical Frequency: 60 Hz
Max Horizontal Frequency: 100 Khz
Minimun Refresh Rate: 60 Hz Min Bandwidth: 20 Mhz
Min Horizontal Frequency: 30 Khz
ModeLine "name" dotclock width x x x heigth y y y #RefreshRate
ModeLine "1280x1024" 110.31 1280 1336 1616 1728 1024 1026
1038 1064 #60Hz
http://zaph.com/Modeline/
# 1280x1024 @ 60Hz, 63.42 kHz hsync
Mode "1280x1024"
DotClock 100.96
HTimings 1280 1312 1416 1592
VTimings 1024 1027 1030 1057
EndMode
sean
