Console:

    *

      You might want to modify /boot/grub/menu.lst, to set vga=871. 

X-Window with vesa driver:

    *

      Lenny will use the vesa driver.
    * OpenGL acceleration: ?
    *

      X-Randr: Trying to change the resolution /!\ kills Xorg !
    * To enable/use the external monitor, you need to reboot the laptop (and close the lid before ASAP).
    *

      During the test, external monitor, only support resolution < 1680x1200 
X-Window with intel driver:

    *

      {i} Note: The intel driver is intentionally not used by default on these chipsets in lenny as it's a backport and it hasn't been tested enough. (see 513080).
    *

      You can reconfigure /etc/X11/xorg.conf to use the intel driver:

      Section "Device"
              Identifier      "Configured Video Device"

              # Add this line to force the driver
              Driver          "intel"
      EndSection

Check with: glxinfo |grep direct