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Old 10-27-2006, 03:39 PM   #1
Odyssey1942
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Resolution mysteriously changed-Round 2


When I first installed Ubuntu 5.04 on this computer it was at home and driving a Sceptre V7 19" monitor and the resolution was fine (1280x1024), but when I took it to the office and hooked it up to the 17" lcd Princeton monitor there, the only resolution that would work was 800 X 600 (approx, this from memory, might have been 640x480).

The problem was resolved, if I recall correctly, by installing a new driver, not for the monitor but for the NVidia video card. (Can't get my head around why the NVidia card worked OK on the 19" mon at home, but would not drive the 17" Princeton AND the solution was a new video driver, but anyway...) I think there needed some lines (dealing with resolution) added to some file also, but memory is very dim on this and my extensive googling is not turning up anything and can't understand this either, but anyway...

I came into the office to find the monitor in 800x600 (or 640x480, as the case may be) and the GUI "System/Screen Resolution" giving me no other option, so why was the screen resolution changed (everyone claims that they did not change anything) and where did the 1280x1024 option in "Screen Resolution" go?

Apologies for not keeping a record of what I did initially to cure it (and for not being able to google it up) as I hate reinventing the wheel, but any guidance to help me get the system back on track would be greatly appreciated.
 
Old 10-27-2006, 06:33 PM   #2
bigjohn
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Well I've had quite similar problems with various distros. It appears (to me) that it's connected with the mobo, graphics card, mobo setup and distro.

With some distros (mandriva, gentoo) my system would give an OK implementation of either Xfree86 or the more recent Xorg "X" server (running the graphics), whereas others, (kubuntu, kanotix and a couple of others) would only allow up to 800 x 600 (instead of the 1600 x 1200 that I usually use), and I'd have to slow the refresh rate down to 60 hz, otherwise the monitor would be unusable, except by shutting down the X server and relying on CLI and doing commands manually.

All the above snags were cured by installing the proprietary nvidia driver, and getting rid of the generic "nv" or "vesa" driver(s).

Fortunately, I feel quite at home with kanotix (like the *buntu's, it's debian based) as the updating is very straight forward (and unlike kubuntu, it doesn't give me crap about not letting me install some development libs so that I can try some of the gimp plugins).

If you or someone else ran an update, later, as opposed to straight after installation, then it may have been that there was a kernel upgrade available, which knocks out the nvidia driver on most distros, and results in either no X server, or revertion to generic "nv" in others. It maybe that you just didn't save some new settings, otherwise I can't think of any other reasons why you might have experienced a "mystery change of resolution" (apart from meddling fingers - someone elses of course).

regards

John

Last edited by bigjohn; 10-27-2006 at 06:34 PM.
 
Old 10-27-2006, 06:41 PM   #3
lurko
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the GUI options for resolution will depend on what resolutions are specified in xorg.conf (or XF86Config). If it isn't specified there, it probably won't show up in GUI tools.

This file is generally located in /etc/X11

my example is obviously limited, resolution-option-wise, you can find a list of modes supported (by your video card mind), at least with Nvidia, in /etc/log/Xorg.0.log. And you can add as many or as few as you like to the config file:
Code:
Section "Screen"
    Identifier  "CRT"
    Device      "CRT"
    Monitor     "CRT"
    DefaultDepth 24
    Subsection "Display"
        Depth       24
        Modes       "1600x1200_85" "1280x1024_85" "1024x768_85" "800x600_85"
    EndSubsection
EndSection
and if you change the monitor attached to a linux computer, you should also change the settings in xorg.conf to reflect the new VertRefresh and HorizSync settings.

Code:
Section "Monitor"
    Identifier  	"CRT"
    HorizSync   	31.5 - 100.0
    VertRefresh 	48.0 - 120.0
    Option 		"DPMS"
EndSection
those settings are for my 19" monitor, possibly similar to other 19" monitors, but I couldn't say. What I can say is that it's a bad idea to use the setttings for any 19" monitor on a 17" monitor - that is just asking for a damaged monitor.
 
Old 10-27-2006, 06:56 PM   #4
bigjohn
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Hum? Whereas, those same sections for mine, look like this
Quote:
Section "Monitor"
Identifier "Monitor0"
Option "DPMS" "true"
DisplaySize 405 306
VendorName "PHL"
ModelName "PHL1021"
# HorizSync 28.0 - 78.0 # Warning: This may fry very old Monitors
HorizSync 28.0 - 96.0 # Warning: This may fry old Monitors
VertRefresh 50.0 - 75.0 # Very conservative. May flicker.
# VertRefresh 50.0 - 62.0 # Extreme conservative. Will flicker. TFT default.
# These are the DDC-probed settings reported by your monitor.
# 1280x1024, 85.0Hz; hfreq=91.15, vfreq=85.02
ModeLine "1280x1024" 157.50 1280 1344 1504 1728 1024 1025 1028 1072 +hsync +vsync
# 1024x768, 85.0Hz; hfreq=68.68, vfreq=85.00
ModeLine "1024x768" 94.50 1024 1072 1168 1376 768 769 772 808 +hsync +vsync
# 1024x768, 75.0Hz; hfreq=60.02, vfreq=75.03
ModeLine "1024x768" 78.75 1024 1040 1136 1312 768 769 772 800 +hsync +vsync
# 800x600, 85.0Hz; hfreq=53.67, vfreq=85.06
ModeLine "800x600" 56.25 800 832 896 1048 600 601 604 631 +hsync +vsync
# 800x600, 75.0Hz; hfreq=46.88, vfreq=75.00
ModeLine "800x600" 49.50 800 816 896 1056 600 601 604 625 +hsync +vsync
# 800x600, 72.0Hz; hfreq=48.08, vfreq=72.19
ModeLine "800x600" 50.00 800 856 976 1040 600 637 643 666 +hsync +vsync
# 640x480, 75.0Hz; hfreq=37.50, vfreq=75.00
ModeLine "640x480" 31.50 640 656 720 840 480 481 484 500 -hsync -vsync
# 640x480, 60.0Hz; hfreq=31.47, vfreq=59.94
ModeLine "640x480" 25.17 640 648 744 784 480 482 484 509 -hsync -vsync
# Extended modelines with GTF timings
# 640x480 @ 100.00 Hz (GTF) hsync: 50.90 kHz; pclk: 43.16 MHz
ModeLine "640x480" 43.16 640 680 744 848 480 481 484 509 -HSync +Vsync
# 768x576 @ 60.00 Hz (GTF) hsync: 35.82 kHz; pclk: 34.96 MHz
ModeLine "768x576" 34.96 768 792 872 976 576 577 580 597 -HSync +Vsync
# 768x576 @ 72.00 Hz (GTF) hsync: 43.27 kHz; pclk: 42.93 MHz
ModeLine "768x576" 42.93 768 800 880 992 576 577 580 601 -HSync +Vsync
# 768x576 @ 75.00 Hz (GTF) hsync: 45.15 kHz; pclk: 45.51 MHz
ModeLine "768x576" 45.51 768 808 888 1008 576 577 580 602 -HSync +Vsync
# 768x576 @ 85.00 Hz (GTF) hsync: 51.42 kHz; pclk: 51.84 MHz
ModeLine "768x576" 51.84 768 808 888 1008 576 577 580 605 -HSync +Vsync
# 768x576 @ 100.00 Hz (GTF) hsync: 61.10 kHz; pclk: 62.57 MHz
ModeLine "768x576" 62.57 768 816 896 1024 576 577 580 611 -HSync +Vsync
# 800x600 @ 100.00 Hz (GTF) hsync: 63.60 kHz; pclk: 68.18 MHz
ModeLine "800x600" 68.18 800 848 936 1072 600 601 604 636 -HSync +Vsync
# 1024x600 @ 60.00 Hz (GTF) hsync: 37.32 kHz; pclk: 48.96 MHz
ModeLine "1024x600" 48.96 1024 1064 1168 1312 600 601 604 622 -HSync +Vsync
# 1024x768 @ 100.00 Hz (GTF) hsync: 81.40 kHz; pclk: 113.31 MHz
ModeLine "1024x768" 113.31 1024 1096 1208 1392 768 769 772 814 -HSync +Vsync
# 1152x864 @ 60.00 Hz (GTF) hsync: 53.70 kHz; pclk: 81.62 MHz
ModeLine "1152x864" 81.62 1152 1216 1336 1520 864 865 868 895 -HSync +Vsync
# 1152x864 @ 85.00 Hz (GTF) hsync: 77.10 kHz; pclk: 119.65 MHz
ModeLine "1152x864" 119.65 1152 1224 1352 1552 864 865 868 907 -HSync +Vsync
# 1152x864 @ 100.00 Hz (GTF) hsync: 91.50 kHz; pclk: 143.47 MHz
ModeLine "1152x864" 143.47 1152 1232 1360 1568 864 865 868 915 -HSync +Vsync
# 1280x768 @ 60.00 Hz (GTF) hsync: 47.70 kHz; pclk: 80.14 MHz
ModeLine "1280x768" 80.14 1280 1344 1480 1680 768 769 772 795 -HSync +Vsync
# 1280x800 @ 60.00 Hz (GTF) hsync: 49.68 kHz; pclk: 83.46 MHz
ModeLine "1280x800" 83.46 1280 1344 1480 1680 800 801 804 828 -HSync +Vsync
# 1280x960 @ 72.00 Hz (GTF) hsync: 72.07 kHz; pclk: 124.54 MHz
ModeLine "1280x960" 124.54 1280 1368 1504 1728 960 961 964 1001 -HSync +Vsync
# 1280x960 @ 75.00 Hz (GTF) hsync: 75.15 kHz; pclk: 129.86 MHz
ModeLine "1280x960" 129.86 1280 1368 1504 1728 960 961 964 1002 -HSync +Vsync
# 1280x960 @ 100.00 Hz (GTF) hsync: 101.70 kHz; pclk: 178.99 MHz
ModeLine "1280x960" 178.99 1280 1376 1520 1760 960 961 964 1017 -HSync +Vsync
# 1280x1024 @ 100.00 Hz (GTF) hsync: 108.50 kHz; pclk: 190.96 MHz
ModeLine "1280x1024" 190.96 1280 1376 1520 1760 1024 1025 1028 1085 -HSync +Vsync
# 1368x768 @ 60.00 Hz (GTF) hsync: 47.70 kHz; pclk: 85.86 MHz
ModeLine "1368x768" 85.86 1368 1440 1584 1800 768 769 772 795 -HSync +Vsync
# 1400x1050 @ 60.00 Hz (GTF) hsync: 65.22 kHz; pclk: 122.61 MHz
ModeLine "1400x1050" 122.61 1400 1488 1640 1880 1050 1051 1054 1087 -HSync +Vsync
# 1400x1050 @ 72.00 Hz (GTF) hsync: 78.77 kHz; pclk: 149.34 MHz
ModeLine "1400x1050" 149.34 1400 1496 1648 1896 1050 1051 1054 1094 -HSync +Vsync
# 1400x1050 @ 75.00 Hz (GTF) hsync: 82.20 kHz; pclk: 155.85 MHz
ModeLine "1400x1050" 155.85 1400 1496 1648 1896 1050 1051 1054 1096 -HSync +Vsync
# 1400x1050 @ 85.00 Hz (GTF) hsync: 93.76 kHz; pclk: 179.26 MHz
ModeLine "1400x1050" 179.26 1400 1504 1656 1912 1050 1051 1054 1103 -HSync +Vsync
# 1400x1050 @ 100.00 Hz (GTF) hsync: 111.20 kHz; pclk: 214.39 MHz
ModeLine "1400x1050" 214.39 1400 1512 1664 1928 1050 1051 1054 1112 -HSync +Vsync
# 1440x900 @ 60.00 Hz (GTF) hsync: 55.92 kHz; pclk: 106.47 MHz
ModeLine "1440x900" 106.47 1440 1520 1672 1904 900 901 904 932 -HSync +Vsync
# 1440x1050 @ 60.00 Hz (GTF) hsync: 65.22 kHz; pclk: 126.27 MHz
ModeLine "1440x1050" 126.27 1440 1536 1688 1936 1050 1051 1054 1087 -HSync +Vsync
# 1600x1200 @ 100.00 Hz (GTF) hsync: 127.10 kHz; pclk: 280.64 MHz
ModeLine "1600x1200" 280.64 1600 1728 1904 2208 1200 1201 1204 1271 -HSync +Vsync
# 1680x1050 @ 60.00 Hz (GTF) hsync: 65.22 kHz; pclk: 147.14 MHz
ModeLine "1680x1050" 147.14 1680 1784 1968 2256 1050 1051 1054 1087 -HSync +Vsync
# 1920x1200 @ 60.00 Hz (GTF) hsync: 74.52 kHz; pclk: 193.16 MHz
ModeLine "1920x1200" 193.16 1920 2048 2256 2592 1200 1201 1204 1242 -HSync +Vsync
EndSection

-----%<-----

Section "Screen"
Identifier "Screen0"
Device "Card0"
Monitor "Monitor0"
DefaultColorDepth 24
SubSection "Display"
Depth 1
Modes "1600x1200" "1280x1024" "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 4
Modes "1600x1200" "1280x1024" "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 8
Modes "1600x1200" "1280x1024" "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 15
Modes "1600x1200" "1280x1024" "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 16
Modes "1600x1200" "1280x1024" "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 24
Modes "1600x1200" "1280x1024" "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 32
Modes "1600x1200" "1280x1024" "1024x768" "800x600" "640x480"
EndSubSection
EndSection
And the H and V refresh rates were auto configured - but my monitor (21" Philips 201B) can take much wider freq's than above, but I don't care, as it's working fine.

regards

John
 
Old 10-27-2006, 09:10 PM   #5
lurko
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I originally setup my xorg.conf file on Slackware, using one the config tools that comes with it, xorg-config or some such. It asked all the questions it needed to answer to create an xorg.conf file, and I used the information I had gathered earlier to answer. I had found out the specs for my monitor and plugged them in here, and I have essentially been using the same xorg.conf file with all the distros I've tried, editing it here and there along the way.

I have never needed to use modelines, and "1600x1200_85" is accepted as a valid mode according to the log (as are the others). I was under the impression that modelines were old school and not required with the "latest" Xorg - I have only been using Linux for a few months now though, and my experience only goes back as far as about Xorg 6.8 (whichever was in Slack 10.2). It could be that specifying resolution and refresh rate in that manner is only valid with a current/ish official nvidia module, but I do recall using the same xorg.conf with the vesa driver (before I installed the nvidia module) and having no problems apart from 1024x768 being the max resolution it would run.

since I've found that 24 bit Depth works fine with my configuration and I don't use anything else, I got rid of all the other depths, which makes xorg.conf that much easier to read. I can see adding a 16 bit subsection if there was a game I wanted to play at 16 bit for some reason, and at one point I had 2 colour depth subsections with one for 16, but I guess that got nixed along the way. I haven't been playing many games lately.

I believe the danger to a monitor comes from exceeding its range, not from failing to. Do most distros check to see if it's the same monitor on every boot? I'm sure that many don't, and I believe after the initial installation, most probably just take what's in xorg.conf and try to run with it. So it's not necessarily a good practice to just swap out a monitor and not at least check xorg.conf to see the settings are appropriate
 
Old 10-29-2006, 12:53 PM   #6
bigjohn
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Quote:
Originally Posted by lurko
my experience is still extremely limited. please take the time to correct me if/when I post erronious information. You will be helping me as well as the person I had been attempting to help. ch-ch-pah!
Ok. Should have started with a capital M, "please" should have a capital p as it's at the start of a sentence and you should be spelling erroneous like this, not with an i.

Otherwise a nice, helpful response.

Piss takes aside, these bloody xorg.conf files all seem to differ, from distro to distro. The one you posted, proves that lots of "them" will have the modelines in there, even though, if you know enough (or are just one of those who like minimalism/brevity), you can edit it down so that it only contains enough to run the X server to your own satisfaction.

My monitor is an aging 21" business model (philips 201B), but I'd bet real cash money (not match sticks) that an LCD/TFT model wouldn't have auto configured with so many modelines as my example - I understand that they only work properly when used with the devices native resolution (but my understanding might be wrong).

Hopefully, the original postee, will have gleaned enough to work out how it's done (seeing as how they haven't posted back).

regards

John
 
Old 10-29-2006, 02:33 PM   #7
lurko
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doh! I knew how to spell erroneous at one point too. however I ceased to care about the proper use of capital letters in most situations except (but not always) with names and "I" years ago. my communinication skills may not be that great, but my grammar skills are superior to those of many(but certainly not all) you'll find online, despite my laziness regarding capital letters. sometimes I'm good about using them, sometimes I'm not. thanks for the notice though, I expect the lack of caps in my sig is going to start irritating me now - perhaps even enough to change it.

glad you approved otherwise, and that I haven't been spouting all sorts of crazy xorg misinformation. I do read manuals and the like, but my memory(and the many-splendored way of *nix) is such that I'm never sure what I think applies, or is so, actually does, or is.

my understanding regarding LCD/TFT panels is the same. native resolution being the only way to go.


btw Grandad needs his glass eye to look for a job. Grandma needs it too, but she didn't say why. And the apostrophe goes between the d and the s, unless of course, he goes by "Grandads". you asked for it!
 
Old 10-29-2006, 08:28 PM   #8
Odyssey1942
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Bigjohn and Lurko,

Aside from an out-of-town trip, I am still around, but being very much a noob, am somewhat overawed by the posts which I am nonetheless reading with interest. They certainly give me a lot to think about and to research further.

Thank you both.

Hopefully, I will be back to the office tomorrow and will give it a go and come back with a report.
 
Old 10-30-2006, 03:18 PM   #9
bigjohn
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Quote:
Originally Posted by Odyssey1942
Bigjohn and Lurko,

Aside from an out-of-town trip, I am still around, but being very much a noob, am somewhat overawed by the posts which I am nonetheless reading with interest. They certainly give me a lot to think about and to research further.

Thank you both.

Hopefully, I will be back to the office tomorrow and will give it a go and come back with a report.
Da nada my friend, thats what LQ is for

regards

John
 
Old 10-30-2006, 03:24 PM   #10
bigjohn
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Quote:
Originally Posted by lurko
-----%<-----
btw Grandad needs his glass eye to look for a job. Grandma needs it too, but she didn't say why. And the apostrophe goes between the d and the s, unless of course, he goes by "Grandads". you asked for it!
Ha ha! good answer Though it wouldn't be so bad, if I hadn't actually read this. Ah well, as a mate of mine used to say (usually after consuming in excess of a litre of Bacardi)

"At the end of the day,
Wherever you go,
There you are".

regards

John
 
Old 11-01-2006, 04:24 PM   #11
Odyssey1942
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OK Here is the result:

Started with:

dpkg-reconfigure xserver-xorg

to reinstall,

and restarted. Voila! Came right up in the correct resolution.

Thanks again for all the thoughts.
 
  


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