Some time after I installed Fedora 10 on my laptop I started noticing that if I tried to use an external projector the only resolution I could get is 800x600, which was a pain. However, I recently discovered that there is a grub boot option 'nomodeset'. That seems to have fixed the problem.
Previously I wrote that I have tested it only on my Belinea monitor not on a projector. However, last week I gave two talks in different places and the xrandr command allowed me to use a resolution of approximately 1200x1024 on two different projectors.
Unfortunately, however, the use of 'nomodeset' in the grub file appears to have stopped 'vlc' showing videos through a projector. So I have been suing gmplayer, which works except that I cannot change the size of display, as I could with vlc.
If anyone knows how to get vlc to display videos on an external projector, with the 'nomodeset' option in the grub boot file, please let me know.
However the problem that vlc does not display videos on the external screen remains, even though mplayer does display them. There should be a simple fix?
At first when I installed Fedora 8 on my laptop, it was somehow configured to use a 'radeon' driver. I don't know where that came from. As I was having problems with that, especially using projectors connected to the laptop, I installed the proprietary self-installing fglrx driver from the ATI linux web site as described here (beware of possibly out of date instructions).
The fglrx driver worked very well for most purposes (including running the 'glxgears' demo much more quickly than the previous driver. However I continued having trouble getting it to work with external displays or projectors. In particular, I typically could not get the laptop to drive an external display unless I aborted the running X11 system and restarted it with the VGA graphic cable connected. Having to restart X was a serious nuisance after I had prepared multiple desktops including demonstrations and videos for a presentation.
I struggled to find a way to set up X11 so that I could connect an external display without restarting X11. I eventually found that I could meet various subsets of these conditions:
I seemed to be able to get any three of those conditions satisfied, but never all of them!
- with the X window system running I should be able to connect an external monitor or projector.
- the external display should be a 'clone' of what is on the screen, as opposed to extending the screen with a separate display area.
- the resolution of the external display should be 1280x1024 (which is what my laptop is set to, though it can do 1400x1050).
- I should not have to restart X after connecting, in order to get the external display working.
I had heard about the wonders of xrandr, e.g. here, and found I had it installed, and tried using it to fix my external display problems. However with the ATI fglrx driver the xrandr commands did not seem to do everything they were supposed to do.
So I decided to go back to a driver packaged by Fedora developers.
After much struggling with solutions found on the internet which may have worked for other systems but did not work for mine, I stumbled on a reference to the 'ati' driver that is available for Fedora, and works with the 'xrandr' utility for manipulating internal and external displays when using X11.
It turned out that my Fedora 8 dvd had this version of the ati driver:xorg-x11-drv-ati-6.7.195-3.fc8.i386So I installed that (I am not sure why it was not included in my original installation). After finding that it did the main things I wanted and also seemed to be compatible with Software Suspend 2 (SWSUSP2, now called Tuxonice) described in my main laptop web page, I usedyum update xorg-x11-drv-atito install the latest version, which turned out to be this:xorg-x11-drv-ati-6.8.0-4.fc8
I now find that I can set up my computer without connecting it to a display, and when ready connect it to an external display, which now works.
The commandxrandr -qprints out information about available displays and their available resolutions.
I can also give this command (after connecting the graphic cable from the projector):xrandr --autoAfter that the display/projector works: no rebooting needed, and no restarting of X11. It also clones the display at the right resolution.
So far I have only tested this on an external LCD monitor. I shall have the chance to test it with an external projector when I give a talk in Newcastle on 21st October. After that event I'll report problems, if any.
There is a simple tutorial on xrandr in http://www.cyberciti.biz/tips/linux-resize-screen-size-quickly.html
E.g if you use the 'xrandr' command to find out the available resolutions for your display, you can number them starting from 0 (corresponding to the default resolution), and use the number as a parameter to specify the resolution to switch to.
E.g. this command will restore the default resolutionxrandr -s 0and if 1024x768 is the 5th resolution in the list then that can be selected usingxrandr -s 5Note that it can take a second or two for the resolution to change.
If you choose a resolution that for some reason does not work, you will have to type in the dark to get back to the original.
More details in this tutorial http://wiki.debian.org/XStrikeForce/HowToRandR12
There is an exception to my claim that 'xrandr' makes everything work with the 'ati' driver, though not with the 'fglrx' driver.
The exception is that when I try using 'vlc' to display movies/videos, they show up fine on my laptop screen, but the display is blank (i.e. black) on the external screen.
Fortunately the problem goes away if I use 'gmplayer' instead of 'vlc'. I suspect that means that vlc can somehow be altered to do the same as gmplayer.
My version of /etc/X11/xorg.conf is available with some annotation here here, as it was on 18 Oct 2008
It also includes the output of 'xrandr' as a comment at the end.
This web site was first created 18 Oct 2008