External monitor on Acer TM 620

[Martin Vlk <vlcak01@tiscali.cz>]

Hi folks,
my laptop has a dual-head i830M graphics and I would like to use is for 
attaching an external monitor or projector.
Now, the X server seems to recognize the second head (see the relevant log 
snippets below), but the attached monitor doesn't display anything. Any idea 
what else needs to be done to activate the second display?

(**) |-->Screen "Default Screen" (0)
(**) |   |-->Monitor "Default LCD Panel"
(**) |   |-->Device "Primary Video Card"
(**) |-->Screen "Secondary Screen" (1)
(**) |   |-->Monitor "Secondary Monitor"
(**) |   |-->Device "Secondary Video Card"
(**) |-->Input Device "Generic Keyboard"

(--) PCI:*(0:2:0) Intel Corp. 82830 CGC [Chipset Graphics Controller] rev 3, 
Mem @ 0x98000000/27, 0x90100000/19
(--) PCI: (0:2:1) Intel Corp. 82830 CGC [Chipset Graphics Controller] rev 0, 
Mem @ 0x88000000/27, 0x80200000/19

(II) I810(0): 2 display pipes available.

(II) I810(0): Display Info: CRT: attached: FALSE, present: TRUE, size: 
(800,600)
(II) I810(0): Display Info: TV: attached: FALSE, present: TRUE, size: 
(800,600)
(II) I810(0): Display Info: DFP (digital flat panel): attached: FALSE, 
present: FALSE, size: (0,0)
(II) I810(0): Display Info: LFP (local flat panel): attached: TRUE, present: 
TRUE, size: (1024,768)
(II) I810(0): Display Info: TV2 (second TV): attached: FALSE, present: FALSE, 
size: (0,0)
(II) I810(0): Display Info: DFP2 (second digital flat panel): attached: FALSE, 
present: FALSE, size: (0,0)
(II) I810(0): Size of device LFP (local flat panel) is 1024 x 768
(II) I810(0): Currently active displays on Pipe A:
(II) I810(0):  LFP (local flat panel)
(II) I810(0): Lowest common panel size for pipe A is 1024 x 768
(II) I810(0): No active displays on Pipe B.

(II) I810(0): maxBandwidth is 640 Mbyte/s, pipe bandwidths are 126 Mbyte/s, 0 
Mbyte/s

Thanks
vlcak