If you're new here, you may want to subscribe to my RSS feed and if you have questions related to your ubuntu system post question to our forums. Thanks for visiting!
Dynamically testing different resolutions
You can either use the Screen Resolution GUI tool to experiment with different resolutions, or the more powerful xrandr command-line tool this shows you the names of different outputs available on your system (LVDS, VGA-0, etc.) and resolutions available on each.
xrandr
or
You can direct xrandr to set a different resolution using the following command
xrandr
--output VGA--mode 1024×768--rate 75
Add undetected resolutions
Due to buggy hardware or drivers, your monitor’s correct resolutions may not always be detected
If the mode already exists, but just isn’t associated for the particular output using the following command
xrandr
--addmode VGA 1024×768
Note:-These changes you make using xrandr only last through the current session.
Set xrandr changes persistently
There are several ways to make xrandr customizations permanent from session to session:
a) .xprofile
A user’s ~/.xprofile file is executed on Xorg startup if it exists and is executable. You can copy and paste xrandr command line strings into this file so they’re executed when you log in
b) kdm/gdm
Both KDM and GDM have startup scripts that are executed when X is initiated. For GDM, these are in /etc/gdm/, while for KDM this is done at /etc/kde4/kdm/Xsetup. In either case, you can paste in an xrandr command line string into one of these scripts.
This process requires root access and mucking around in system config files, but will take effect earlier in the startup process than using .xprofile, and will apply to all users including the login screen.
c) xorg.conf
See man xorg.conf for full details on how to use an xorg.conf file.Check man page from here
I still use system->manage
Remember if you have an nvidia card setup its best to use nvidia-settings to manage your screen(s)…
Nice granular control for displaying laptop pictures on a TV or other screen.
Correct me if I am wrong but this tool is primarily for open source drivers: If using proprietary drivers from Intel, nVidia or ATI/AMD you would be wise to use their tool.
Will it control proprietary drivers?
xrandr seems to show not more than was recognised during installation of the system. I made myself an USB stick with Knoppix 6.0 (also Debian!) and discovered a new world of screen resolutions possible on my hardware (it is one of the mainboards with integrated graphics chip, giving ubuntu a tough time recognising it). Since xorg.conf seems to do less and less of the settings, I had only limited success in copying screen information from Knoppix to ubuntu. On startup I have to click through 3 error windows until the desired 1600×1200 resulution is started as “low resolution graphics”.
It is not annoying but I feel for telling this to the world.
found out that xrandr shows the same as System->adjustments->screen resolution.
I have problems with motherboards with integrated video card. Xorg does not recognise most of them to be useful.
I got myself a Knoppix 6 usb stick which obviously does a better job. The xorg.conf file I copied from the stick to ubuntu /etc/X11
This works - mostly, some older CRT monitors loose over time their ability to run at high resolution (even if specified) and automagically switch back to something lower. I did not find a way to refurbish them, even if higher resolution is forced, an annoying flicker is the result.
Knoppix is something very usefull, more than one time it helped me out in repairing ubuntu, I find it more versatile than the “repair booting” of the ubuntu install CD.
I forgot to mention that in Knoppix the monitor ia always running in highest possible resolution, without flickering and over hours. Just when back in ubuntu I get this auto-setback and/or flicker. No idea why.
how do you install a SiS driver? i think mine is not supported by ubuntu 8.04?
I have mainboard with Athlon 64bit 3000+ (but running 32 bit ubuntu). Systemspeed 4.70 (DOS)program unveils SiS chipset with 86C202 graphics accelerator on board. I did as above start with Knoppix 6.0.1 on stick, copy the Knoppix xorg.conf to ubuntu file system and restart. Result is not satisfying however, I am not able to get max. resolution in ubuntu (8.10) though Knoppix runs fine at it. Hope that 9.04 will solve the problem when upgrading.
Thanks for the xrandr command, but there’s a mistake in the depiction of the command. There is no space between the double dashes and the command.
For example, the first command above should read:
xrandr
--output VGA--mode 1024×768--rate 75Regarding aging CRT monitors, perhaps a word on *maintenance* is in order!
-
Over time the CRT - and to some extent, the high voltage circuits - age. This is not necessarily the end however. Servicing requires two things, a bit of intuition regarding how to pry open the case after removal of the screws, and unless you have a proper servicing stand, a second person to hold the thing whilst it is adjusted. Yes, the insides *are* dangerous but with due precautions, workable.
-
Tracking the high voltage lead from the “Ultor” connector on the tube to the tripler assembly, it will be found to have two adjustments on it. One is FOCUS and adjustment will allow the original screen resolution to be restored. The other is SCREEN and can often be adjusted to restore lost screen brightness. It also affects the focus, so FOCUS is the last to be adjusted.
-
Need I say, these are adjusted with a long blade, well insulated (which refers more to the amount of plastic in the handle, than having an insulated shaft) “blade” screwdriver of the correct calibre for the adjusters (about 3 to 4 mm wide). Obviously you have to have text on the screen and be able to see the screen, and you have to allow the display to warm up for 5 minutes first. The final task is to reassemble the monitor and not have any parts sticking out or pieces left over.
-
There is however no “automagically switching back to something lower” in a CRT monitor - the monitor only “knows” its specified (maximum) resolution, it has no awareness of losing focus. And aliasing is an analog process (unlike CRT monitors, some of which make a terrible job of it).