Voilà donc un résumé de l"installation d'une debian lenny (5.0) sur un portable Dell Latitude.

Configuration du serveur graphique (X) :

Mon gros problème venait du xorg.conf qui ne se générait pas correctement, au lancement du serveur X l'écran est comme divisé en trois. Voici donc celui qui a fonctionné:

 Section "ServerLayout"

Identifier "MyLayout"
Screen "Screen0"
InputDevice "Internal" "CorePointer"
InputDevice "USBMouse" "SendCoreEvents"
InputDevice "Keyboard0" "CoreKeyboard"
Option "BlankTime" "5"
Option "StandbyTime" "10"
# Option "SuspendTime" "40"
EndSection

Section "Files"
FontPath "unix/:7100"
EndSection

# This loads all the modules...

Section "Module"
Load "dri"

Load "GLcore"
Load "dbe"
Load "extmod"
Load "glx"
Load "pex5"
Load "record"
Load "xie"
Load "v4l"
Load "freetype"
EndSection

Section "InputDevice"
Identifier "Keyboard0"
Driver "keyboard"
Option "XkbLayout" "fr"
Option "XkbModel" "pc104"
Option "AutoRepeat" "250 30"
EndSection

Section "InputDevice"
Identifier "Internal"
Driver "mouse"
Option "Device" "/dev/psaux"
Option "Protocol" "PS/2"
Option "Emulate3Buttons" "on"
EndSection

Section "InputDevice"
Identifier "USBMouse"
Driver "mouse"
Option "Device" "/dev/pointer"
Option "Name" "AutoDetected"
Option "Protocol" "IMPS/2"
Option "Vendor" "AutoDetected"
Option "ZAxisMapping" "4 5"
EndSection

Section "Monitor"
Identifier "LCD"
VendorName "Dell"
ModelName "I8K"
HorizSync 28-90
VertRefresh 40-110
Option "DPMS"
EndSection

Section "Monitor"
Identifier "Sony"
VendorName "Sony"
ModelName "GDM-500PS"
HorizSync 30-107
VertRefresh 46-160
Option "DPMS"
EndSection

Section "Device"
Identifier "ATI|Rage Mobility M3 AGP 2x"
Driver "ati"
VideoRam 32768
BoardName "Unknown"
BusID "PCI:1:0:0"
Screen 0
Option "AGPMode" "4"
EndSection

Section "Screen"
Identifier "Screen0"
Device "ATI|Rage Mobility M3 AGP 2x"
Monitor "LCD"
DefaultDepth 16
Subsection "Display"
Depth 32
Modes "1600x1200"
EndSubSection
Subsection "Display"
Depth 24
Modes "1600x1200"
EndSubSection
Subsection "Display"
Depth 16
Modes "1600x1200" "1280x1024" "1024x768" "800x600"
EndSubSection
EndSection

Section "DRI"
Mode 0666
EndSection