Here's what I would try.
Originally Posted by rocky_raccoon
That should put the discreet card first in the xorg.conf as well as the Monitor/Screen also the HDMI is a DFPx (x being the port number not sure what you're setup looks like) and sofar all my experience with ATI cards the HDMI are numbered first when there are DVI ports as well.
mv xorg.conf xorg.conf.bak
aticonfig --adapter=1,0 --initial
On my 5970 there is 3 ports one mini display (mine hdmi) which is DFP1 and the the two DVI ports DFP2 and DFP3
On my 5870 there is x2 HDMI x2 DVI and yet again my HDMI ports are DPF1 DPF2 then DVI ports are DFP3 and DFP4
Now I have a tower and you're using a laptop so I don't know what they or how you have things sticking out and where lol, in my case If I'm leaning over from the front of my tower looking down at the Display ports from left to right on both cards would start the order 5970 DPF2 DVI, DPF1 HDMI ,DPF3 DVI (Even though they stuck the HDMI in the Middle it's still DPF1 and it's still left to right with the DVI's) Then my 5870 DPF1 HDMI, DPF2 HDMI, DPF3 DVI, DPF4 DVI.
So with that said you if you only have one HDMI port it should be DPF1 for the spefic card the HDMI port is for. then you need something like this in your xorg.conf:
I made this via the aticonfig command real quick(just for you =) for a pure basic config and edited out the extra displays to lessen your confusion to be used as an example. As I backed up my custom setup first like above.
I'm using my 5970 as the first card connected via a DVI the port is DPF2 (I'm using DVI because I need a Dual Link DVI(which basically means more pins) to obtain the 120Hz).
Hope this sheds more light then confuses you lol.
Identifier "aticonfig Layout"
Screen 0 "aticonfig-Screen-0" 0 0
Option "VendorName" "ATI Proprietary Driver"
Option "ModelName" "Generic Autodetecting Monitor"
Option "DPMS" "true"
Option "PreferredMode" "1920x1080"
Option "TargetRefresh" "120"
Option "Position" "0 0"
Option "Rotate" "normal"
Option "Disable" "false"
Option "Monitor-DFP2" "0-DFP2"
Viewport 0 0
Just one more thing you should be able to setup your BIOS to your desired Display Adapter just another resort you can try as well then just need too run the --initial that should straighten things out as well.