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My laptop supports 1366x768 resolution but, even after installing Guest Additions on my lubuntu-11.10-alternate-i386 virtual machine I have as available resolutions only (from xrandr):

   1024x768       60.0 +   60.0  
   1600x1200      60.0  
   1440x1050      60.0  
   1280x960       60.0  
   800x600        60.0* 
   640x480        60.0  
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up vote 2 down vote accepted

Please check out my post here:


# Script to automatically resize virtual monitors in VirtualBox

# Start the server
sudo killall VBoxService
sleep 1
sudo VBoxService
sleep 1

# Start the client service

# Get the modeline information we want for the following resolutions:
# 1680x1050@60.00Hz (Laptop display)
RES0="1680 1050 60"
# 1280x1024@60Hz (External monitor)
RES1="1280 1024 60"

# Setup mappings for physical to virtual monitors

# Generate settings
SETTINGS0=$( gtf $RES0 | grep Modeline | cut -d ' ' -f4-16 )
SETTINGS1=$( gtf $RES1 | grep Modeline | cut -d ' ' -f4-16 )

# Get name of modelines from settings
NAME0=$( echo $SETTINGS0 | cut -d ' ' -f1 )
NAME1=$( echo $SETTINGS1 | cut -d ' ' -f1 )

# Echo settings
echo "Modeline for Display 0 ($NAME0): $SETTINGS0"
echo "Modeline for Display 1 ($NAME1): $SETTINGS1"

# Create the new modelines via xrandr
xrandr --newmode $SETTINGS0
xrandr --newmode $SETTINGS1

# Add the newly created modelines to devices
xrandr --addmode $MAP0 $NAME0
xrandr --addmode $MAP1 $NAME1

# Finally, enable the new modes
xrandr --output $MAP0 --mode $NAME0
xrandr --output $MAP1 --mode $NAME1

# Extra: Attempt to run "auto" mode on the external monitor
# This is out last-ditch effort (which worked in this case) to get it running at
# 1600x1200 instead of 1280x1024 :)
xrandr --output $MAP1 --auto --above $MAP0

You can then just put this in your rc file (kderc, gtkrc-2.0, fvwm2rc) to run and then restart the desktop manager. Everything should look great!

Please note that the only extra bit of code in here is the --above $MAP0 argument, which means that the monitor for MAP0 is physically located above MAP0.

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