A Newbie's Guide To RandR 1.2

[phoronix]

Phoronix: A Newbie's Guide To RandR 1.2

Recently there has been much talk about RandR 1.2 support with RadeonHD and Nouveau (among other drivers), and as a result we have been asked many times now "what is RandR, and why do I care?" Well, RandR is the "Resize and Rotate" extension in X.Org and the v1.2 update introduces new functionality such as dynamic hot-plugging support for display devices. To help those who may be new to Linux or just never took advantage of this X.Org technology, we have written a brief guide with some of the RandR basics.

http://www.phoronix.com/vr.php?view=11485

[Tsiolkovsky]

You should also add to the article that Mandriva Linux 2008 was released with RandR applet for KDE. More info here (http://wiki.mandriva.com/en/Releases/Mandriva/2008.0/Tour#RandR_1.2_applet_for_KDE).

[NilsHG]

Thank you phoronix!
Still being fairly new to Linux (ubuntu in particular, I started with 7.04) I once again realised the CLI is of far more use than any GUI workaround. grandr kept crashing on my system but everything works fine with xrandr. This report is just what I needed!

Keep up the good work!:)

[shamooki]

Thanks for the article! I've been searching for a primer on xrandr for quite some time now.

However, I wonder if I can make any use of xrandr's display switching features when using the ATI fglrx-Driver.

shamooki

[Michael]

However, I wonder if I can make any use of xrandr's display switching features when using the ATI fglrx-Driver.

Hi,

Not right now you can't as the fglrx driver currently isn't compliant with RandR 1.2. However, that could change in the not so distant future. Right now you need to use aticonfig (see aticonfig --help).

[Danniello]

It is possible to create virtual resolution with xrandr?
For example: Screen size is 1600x1200 but on monitor it is displayed 1024x768 and I can move screen with mouse...

[seba]

Great article...
oh there is one little typo in the second paragraph it says "RandR stands for Reside and Rotate" :)

[CrystalCowboy]

It is possible to create virtual resolution with xrandr?
For example: Screen size is 1600x1200 but on monitor it is displayed 1024x768 and I can move screen with mouse...

Yes. with an xorg.conf file, a line goes in the "Display" subsection of the "Screen" section. I'm not sure if this is possible with the CLI, or what the syntax would be.

Here's a sample xorg.conf file for the radeon driver under Fedora 8.


Section "ServerLayout"
Identifier "RandR Multihead layout"
Screen 0 "Screen0" 0 0
InputDevice "Keyboard0" "CoreKeyboard"
EndSection

Section "InputDevice"
Identifier "Keyboard0"
Driver "kbd"
Option "XkbModel" "pc105"
Option "XkbLayout" "us+inet"
EndSection

Section "Monitor"
Identifier "DVI-0"
ModelName "Acer AL2216W"
Option "PreferredMode" "1680x1050"
Option "DPMS" "on"
EndSection

Section "Monitor"
Identifier "DVI-1"
ModelName "Acer AL2216W"
Option "PreferredMode" "1680x1050"
Option "RightOf" "DVI-0"
Option "DPMS" "on"
EndSection

Section "Device"

# BusID "PCI:1:0:0"
Identifier "Videocard0"
Driver "radeon"
BoardName "Radeon X1050"
EndSection

Section "Screen"
Identifier "Screen0"
Device "Videocard0"
Monitor "DVI-0"
DefaultDepth 24
SubSection "Display"
Viewport 0 0
Virtual 3360 1050
Depth 24
EndSubSection
EndSection




Right now the naming of display outputs and the recognition of particular RandR lines in xorg.conf varies slightly between the various drivers. I hope there is some convergence on this in the future.

[Danniello]

SubSection "Display"
Virtual 3360 1050

It's working with nVidia too!
Thank you! Now screenshot 3200x2400 for example maps.google.com is not a problem:)

[jidanni]

I feel so stupid. I thought my IBM Thinkpad could use 800x600
(see bugs.debian.org/cgi-bin/bugreport.cgi?bug=456955 )
but I can't manage it anymore. All I get is younger users laughing at me.
$ xrandr --fb 800x600
xrandr: specified screen 800x600 not large enough for output LVDS (1024x768+0+0)
does that mean that no matter even if one day I am told what to put in
xorg.conf, I will never be able to get less that 1024x768?

[CrystalCowboy]

jidanni: Take a look around in your BIOS and see if something there is determining the LVDS resolution.

Although if you 1024x768 pixels, why would you want to run at reduced resolution?

[greg]

$ xrandr --fb 800x600
xrandr: specified screen 800x600 not large enough for output LVDS (1024x768+0+0)
does that mean that no matter even if one day I am told what to put in
xorg.conf, I will never be able to get less that 1024x768?

xrandr --output LVDS --mode 800x600