xrandr
xrandr is an official configuration utility to the RandR (Resize and Rotate) X Window System extension. It can be used to set the size, orientation or reflection of the outputs for a screen. For configuring multiple monitors see the Multihead page.
Installation
Graphical front-ends
- ARandR — Simple visual front end for XRandR. Relative monitor positions are shown graphically and can be changed in a drag-and-drop way.
- LXRandR — Screen resolution and monitor position tool for LXDE. Also works in Openbox.
- https://wiki.lxde.org/en/LXRandR || GTK 2: lxrandr, GTK 3: lxrandr-gtk3
CLI front-ends
- autorandr — Automatically select a display configuration based on connected devices.
- xlayoutdisplay — Detects and arranges displays. Handles: laptop lid state, highest available refresh rates, calculating and applying the actual DPI. Best used in .xinitrc, then can be invoked when plugging/unplugging monitors or closing laptop lid.
Testing configuration
When run without any option, xrandr shows the names of different outputs available on the system (VGA-1, HDMI-1, etc.) and resolutions available on each, with a * after the current one and a + after the preferred one :
xrandr
Screen 0: minimum 320 x 200, current 3200 x 1080, maximum 8192 x 8192 VGA-1 disconnected (normal left inverted right x axis y axis) HDMI-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 531mm x 299mm 1920x1080 59.93 + 60.00* 50.00 59.94 1920x1080i 60.00 50.00 59.94 1680x1050 59.88 …
You can use xrandr to set different resolution (must be present in the above list) on some output:
$ xrandr --output HDMI-1 --mode 1920x1080
When multiple refresh rates are present in the list, it may be changed by the --rate option, either at the same time or independently. For example:
$ xrandr --output HDMI-1 --mode 1920x1080 --rate 60
The --auto option will turn the specified output on if it is off and set the preferred (maximum) resolution:
$ xrandr --output HDMI-1 --auto
It is possible to specify multiple outputs in one command, e.g. to turn off HDMI-1 and turn on HDMI-2 with preferred resolution:
$ xrandr --output HDMI-1 --off --output HDMI-2 --auto
- Changes you make using xrandr will only last through the current session.
- xrandr has a lot more capabilities - see xrandr(1) for details.
Configuration
xrandr is just a simple interface to the RandR extension and has no configuration file. However, there are multiple ways of achieving persistent configuration:
- The RandR extension can be configured via X configuration files, see Multihead#RandR for details. This method provides only static configuration.
- If you need dynamic configuration, you need to execute xrandr commands each time X server starts. See Autostarting#On Xorg startup for details. This method has the disadvantage of occurring fairly late in the startup process, thus it will not alter the resolution of the display manager if you use one.
- Custom scripts calling xrandr can be bound to events (for example when external monitor is plugged in), see udev or acpid for details. The #Scripts section provides you with some example scripts that might be useful for this purpose.
/etc/gdm/, while for KDM this is done at /usr/share/config/kdm/Xsetup and for SDDM at /usr/share/sddm/scripts/Xsetup. This method requires root access and mucking around in system config files, but will take effect earlier in the startup process than using xprofile.Scripts
Toggle external monitor
This script toggles between an external monitor (specified by $extern) and a default monitor (specified by $intern), so that only one monitor is active at a time.
The default monitor should be connected when running the script, which is always true for a laptop.
#!/bin/bash
intern=LVDS1
extern=VGA1
if xrandr | grep "$extern disconnected"; then
xrandr --output "$extern" --off --output "$intern" --auto
else
xrandr --output "$intern" --off --output "$extern" --auto
fi
xrandr --output "$intern" --primary --auto --output "$extern" --right-of "$intern" --auto.Manage 2-monitors
monsAUR is a POSIX-compliant shell script to quickly manage 2-monitors display.
It provides well-known modes like computer, duplicate, extend and projector mode as well as selecting and positioning one or two monitors among those plugged in (for more details, see mons).
Example 3
This script iterates through connected monitors, selects currently active monitor, turns next one on and the others off:
# get info from xrandr
connectedOutputs=$(xrandr | awk '$2 == "connected"{print $1}')
activeOutput=$(xrandr | grep -E " connected (primary )?[1-9]+" | sed -e "s/\([A-Z0-9]\+\) connected.*/\1/")
# initialize variables
execute="xrandr "
default="xrandr "
i=1
switch=0
for display in $connectedOutputs
do
# build default configuration
if [ $i -eq 1 ]
then
default=$default"--output $display --auto "
else
default=$default"--output $display --off "
fi
# build "switching" configuration
if [ $switch -eq 1 ]
then
execute=$execute"--output $display --auto "
switch=0
else
execute=$execute"--output $display --off "
fi
# check whether the next output should be switched on
if [ $display = $activeOutput ]
then
switch=1
fi
i=$(( $i + 1 ))
done
# check if the default setup needs to be executed then run it
echo "Resulting Configuration:"
if ! (echo "$execute" | grep -q "auto")
then
echo "Command: $default"
`$default`
else
echo "Command: $execute"
`$execute`
fi
echo
xrandr
Avoid X crash with xrasengan
Use this workaround to turn on connected outputs that may be in suspend mode and hence shown as disconnected, as is often the case of DisplayPort monitors:
declare -i count=2
declare -i seconds=1
while ((count)); do
xrandr >/dev/null
sleep $seconds
((count--))
done
xrasenganAUR is an xrandr wrapper with this workaround built in.
$ xrasengan --force -on DisplayPort-0 -off HDMI-0
With the --force option, xrasengan will update status of all outputs before HDMI-0 is turned off, avoiding an X crash if they were the only connected/active outputs.
To force reload current settings, xrasengan provides a --try-reload-active-layout option, which uses --force and unxrandr from the arandr package to assemble the command line:
$ xrasengan --try-reload-active-layout
This can be used in systemd unit or in a keyboard binding to avoid blank screen when resuming DisplayPort monitors from suspend.
Configuration using arandr
arandr can graphically arrange your monitors, change resolutions, and save a script to duplicate your setup. By default, if you "Save As" it will be saved in ~/.screenlayout/. These files can then be added to your ~/.profile. Sometimes problems arise from running the arandr script too soon after login.
Edit ~/.profile
$ sleep 3 $ /home/<user>/.screenlayout/myLayout.sh
Troubleshooting
Screen Blinking
For some LCD screens (e.g. Samsung 2343NW, Acer XB280HK, iiyama ProLite XUB3490WQSU-B1...), the command cvt -r (i.e. with reduced blanking) is to be used.
E.g with ProLite XUB3490WQSU-B1 and Thunderbolt HDMI 2.0 adapter on Dell XPS 13, with 60hz (59,94 selected) this screen is blinking (and the adapter+LCD screen works perfectly on Windows), you have to do :
cvt -r 3440 1440
Wich giving you :
# 3440x1440 59.97 Hz (CVT) hsync: 88.82 kHz; pclk: 319.75 MHz
Modeline "3440x1440R" 319.75 3440 3488 3520 3600 1440 1443 1453 1481 +hsync -vsync
Then you have to do :
xrandr --newmode "3440x1440R" 319.75 3440 3488 3520 3600 1440 1443 1453 1481 +hsync -vsync
and
xrandr --addmode DP1 3440x1440R
Now you can select 59.97hz mode with the best screen resolution, wich not blinking anymore.
Adding undetected resolutions
Due to buggy hardware or drivers, your monitor's correct resolutions may not always be detected by xrandr. For example, the EDID data block queried from the monitor may be incorrect. However, we can add the desired resolutions to xrandr. Also, this same procedure can be used to add refresh rates you know are supported, but not enabled by your driver.
First we run gtf or cvt to get the Modeline for the resolution we want:
$ cvt 1280 1024
# 1280x1024 59.89 Hz (CVT 1.31M4) hsync: 63.67 kHz; pclk: 109.00 MHz Modeline "1280x1024_60.00" 109.00 1280 1368 1496 1712 1024 1027 1034 1063 -hsync +vsync
- If you find that the screen goes blank when the modeline is applied, try lower refresh rate (e.g. 30 or 45 instead of 60). The refresh rate should be passed as the third argument:
cvt 2560 1440 45.
/var/log/Xorg.0.log — use that first if it is different from the output of gtf or cvt. For instance, the log and its use with xrandr:
[ 45.063] (II) intel(0): clock: 241.5 MHz Image Size: 597 x 336 mm [ 45.063] (II) intel(0): h_active: 2560 h_sync: 2600 h_sync_end 2632 h_blank_end 2720 h_border: 0 [ 45.063] (II) intel(0): v_active: 1440 v_sync: 1443 v_sync_end 1448 v_blanking: 1481 v_border: 0
xrandr --newmode "2560x1440" 241.50 2560 2600 2632 2720 1440 1443 1448 1481 -hsync +vsync
You may also find similar lines for the modesetting driver.
Then we create a new xrandr mode. Note that the Modeline keyword needs to be omitted.
$ xrandr --newmode "1280x1024_60.00" 109.00 1280 1368 1496 1712 1024 1027 1034 1063 -hsync +vsync
After creating it we need an extra step to add this new mode to our current output (VGA1). We use just the name of the mode, since the parameters have been set previously.
$ xrandr --addmode VGA1 1280x1024_60.00
Now we change the resolution of the screen to the one we just added:
$ xrandr --output VGA1 --mode 1280x1024_60.00
Note that these settings only take effect during this session.
If you are not sure about the resolution you will test, you may add a sleep 5 and a safe resolution command line following, like this:
$ xrandr --output VGA1 --mode 1280x1024_60.00 && sleep 5 && xrandr --newmode "1024x768-safe" 65.00 1024 1048 1184 1344 768 771 777 806 -HSync -VSync && xrandr --addmode VGA1 1024x768-safe && xrandr --output VGA1 --mode 1024x768-safe
Also, change VGA1 to correct output name.
EDID checksum is invalid
If the previous method results in an *ERROR* EDID checksum is invalid error during boot, see KMS#Forcing modes and EDID and [2].
Or xrandr --addmode might give you the error X Error of failed request: BadMatch. NVIDIA users should read NVIDIA/Troubleshooting#xrandr BadMatch. BadMatch could indicate an invalid EDID checksum. To verify that this is the case, run X in verbose mode (e.g. startx -- -logverbose 6) and check your Xorg log for messages about a bad EDID.
Screen resolution reverts back after a blink
If you use GNOME and your monitor does not have an EDID, above #Adding undetected resolutions might not work, with your screen just blinking once, after xrandr --output.
Poke around with ~/.config/monitors.xml, or delete the file completely, and then reboot.
It is better explained in this article.
Permanently adding undetected resolutions
Once a suitable resolution is found using xrandr, the mode can be permanently added by creating an entry in /etc/X11/xorg.conf.d/:
/etc/X11/xorg.conf.d/10-monitor.conf
Section "Monitor"
Identifier "VGA1"
Modeline "1280x1024_60.00" 109.00 1280 1368 1496 1712 1024 1027 1034 1063 -hsync +vsync
Option "PreferredMode" "1280x1024_60.00"
EndSection
Section "Screen"
Identifier "Screen0"
Monitor "VGA1"
DefaultDepth 24
SubSection "Display"
Modes "1280x1024_60.00"
EndSubSection
EndSection
Section "Device"
Identifier "Device0"
Driver "intel"
EndSection
Replace intel with the right driver, e.g. nvidia. When the X server is restarted, you should be able to set the new resolution.
If this does not work for you, try removing the Screen and Device sections and just leaving the Monitor section. [3]
Resolution lower than expected
If your video card is recognized but the resolution is lower than you expect, you may try this.
Background: ATI X1550 based video card and two LCD monitors DELL 2408(up to 1920x1200) and Samsung 206BW(up to 1680x1050). Upon first login after installation, the resolution default to 1152x864. xrandr does not list any resolution higher than 1152x864. You may want to try editing /etc/X11/xorg.conf, add a section about virtual screen, logout, login and see if this helps. If not then read on.
Change xorg.conf
/etc/X11/xorg.conf
Section "Screen"
...
SubSection "Display"
Virtual 3600 1200
EndSubSection
EndSection
About the numbers: DELL on the left and Samsung on the right. So the virtual width is of sum of both LCD width 3600=1920+1680; Height then is figured as the max of them, which is max(1200,1050)=1200. If you put one LCD above the other, use this calculation instead: (max(width1, width2), height1+height2).
Correction of overscan tv resolutions via the underscan property
With a flat panel TV, w:overscan looks like the picture is "zoomed in" so the edges are cut off.
Check your TV if there is a parameter to change. If not check if the output has support for the underscan property (xrandr --prop), if so apply an underscan and change border values.
The required underscan vborder and underscan hborder values can be different for you, just check it and change it by more or less.
$ xrandr --output HDMI-0 --set underscan on --set "underscan vborder" 25 --set "underscan hborder" 40
Correction of overscan tv resolutions via --transform
If underscan is not available another solution is using xrandr --transform a,b,c,d,e,f,g,h,i, which applies a transformation matrix on the output. See the xrandr(1) § RandR_version_1.3_options manual page for the explanation of the transformation.
For example, the transformation scaling horizontal coordinates by 0.8, vertical coordinates by 1.04 and moving the screen by 35 pixels right and 19 pixels down, is:
$ xrandr --output HDMI1 --transform 0.80,0,-35,0,1.04,-19,0,0,1
Full RGB in HDMI
It may occur that the Intel driver will not configure correctly the output of the HDMI monitor. It will set a limited color range (16-235) using the Broadcast RGB property, and the black will not look black, it will be grey.
See Intel graphics#Weathered colors (color range problems).
Disabling phantom monitor
In some cases, a non-existent monitor may be detected by the system. To disable it, find the name of the phantom output, e.g. VGA1, and turn it off with
$ xrandr --output VGA1 --off
To make this permanent, add the following to an entry in /etc/X11/xorg.conf.d/:
/etc/X11/xorg.conf.d/10-monitor.conf
Section "Monitor"
Identifier "VGA1"
Option "Ignore" "true"
EndSection
Dynamic interlace pattern artifacts with AOC G2590PX
If you are seeing very prominent interlace pattern artifacts (mesh or grid) when you see movement on the screen with this monitor, it might be happening because of a low refresh rate. Switching to a higher refresh rate (from 60 Hz to 119.98 Hz and perhaps even higher) might help reduce the effect.
Sample xrandr output for this monitor over HDMI:
HDMI-1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 544mm x 303mm 1920x1080 60.00 + 119.98* 99.93 50.00 59.94
As can be seen in the output above, the preferred refresh rate reported by xrandr is 60.00, but the artifacts are very visible with this refresh rate. Switching to 119.98 should help reduce the effect considerably.
$ xrandr --output HDMI-1 --mode 1920x1080 --rate 119.98