EEE: enabling higher resolution of external monitor

External monitors wouldn't get resolutions higher than 1024*768 on the EEE. Although it is supposed to go automatically, it didn't happen in my case. The reason was found by checking the X-window log:

less /var/log/Xorg.0.log

The allowed modes from the monitor are:

(II) intel(0): EDID for output VGA
(II) intel(0): Manufacturer: SAM Model: 1ba Serial#: 1212231993
(II) intel(0): Year: 2006 Week: 50
(II) intel(0): EDID Version: 1.3
(II) intel(0): Analog Display Input, Input Voltage Level: 0.700/0.300 V
(II) intel(0): Sync: Separate Composite SyncOnGreen
(II) intel(0): Max H-Image Size [cm]: horiz.: 38 vert.: 30
(II) intel(0): Gamma: 2.20
(II) intel(0): DPMS capabilities: Off; RGB/Color Display
(II) intel(0): First detailed timing is preferred mode
(II) intel(0): redX: 0.640 redY: 0.329 greenX: 0.300 greenY: 0.600
(II) intel(0): blueX: 0.150 blueY: 0.060 whiteX: 0.313 whiteY: 0.329
(II) intel(0): Supported VESA Video Modes:
(II) intel(0): 720x400@70Hz
(II) intel(0): 640x480@60Hz
(II) intel(0): 640x480@67Hz
(II) intel(0): 640x480@72Hz
(II) intel(0): 640x480@75Hz
(II) intel(0): 800x600@56Hz
(II) intel(0): 800x600@60Hz
(II) intel(0): 800x600@72Hz
(II) intel(0): 800x600@75Hz
(II) intel(0): 832x624@75Hz
(II) intel(0): 1024x768@60Hz
(II) intel(0): 1024x768@70Hz
(II) intel(0): 1024x768@75Hz
(II) intel(0): 1280x1024@75Hz
(II) intel(0): 1152x870@75Hz

The highest virtual mode in /etc/X11/xorg.conf was 1024*768, though, so in the log file one could read:

(II) intel(0): Not using default mode "1280x1024" (height too large for virtual size)
(II) intel(0): Not using default mode "1280x1024" (height too large for virtual size)
(II) intel(0): Not using default mode "1280x1024" (height too large for virtual size)
(II) intel(0): Not using default mode "1400x1050" (height too large for virtual size)
(II) intel(0): Not using default mode "1400x1050" (height too large for virtual size)
(II) intel(0): Not using default mode "1400x1050" (height too large for virtual size)
(II) intel(0): Not using default mode "1400x1050" (height too large for virtual size)
(II) intel(0): Not using default mode "1440x900" (width too large for virtual size)
(II) intel(0): Not using default mode "1600x1024" (width too large for virtual size)
(II) intel(0): Not using default mode "1680x1050" (height too large for virtual size)
(II) intel(0): Not using default mode "1920x1200" (height too large for virtual size)
(II) intel(0): Not using default mode "1920x1200" (height too large for virtual size)
(II) intel(0): Not using default mode "1920x1440" (height too large for virtual size)
(II) intel(0): Not using default mode "2048x1536" (height too large for virtual size)
(II) intel(0): Not using default mode "2048x1536" (height too large for virtual size)
(II) intel(0): Not using default mode "2048x1536" (height too large for virtual size)

The solution: replace in /etc/X11/xorg.conf:

Section "Screen"
Identifier "Screen1"
Device "Device1"
Monitor "Monitor1"
DefaultDepth 16
SubSection "Display"
Depth 8
Virtual 1024 768
EndSubSection
SubSection "Display"
Depth 15
Virtual 1024 768
EndSubSection
SubSection "Display"
Depth 16
Virtual 1024 768
EndSubSection
SubSection "Display"
Depth 24
Virtual 1024 768
EndSubSection
EndSection

by:

Section "Screen"
Identifier "Screen1"
Device "Device1"
Monitor "Monitor1"
DefaultDepth 16
SubSection "Display"
Depth 8
Virtual 1280 1024
EndSubSection
SubSection "Display"
Depth 15
Virtual 1280 1024
EndSubSection
SubSection "Display"
Depth 16
Virtual 1280 1024
EndSubSection
SubSection "Display"
Depth 24
Virtual 1280 1024
EndSubSection
EndSection

Or

Or use higher resolutions, depending on your monitor.