I have this configuration:
on board i845 card and ati9200 card.

When I run X -scanpci and ati9200 is not pluged in I get this:

Probing for PCI devices (Bus:Device:Function)

(0:0:0) Intel Corp. 82845G/GL [Brookdale-G] Chipset Host Bridge
(0:2:0) unknown card (0x0e11/0x00c5) using a Intel Corp. 82845G/GL [Brookdale-G] Chipset Integrated Graphics Device
(0:29:0) unknown card (0x0e11/0x00c5) using a Intel Corp. 82801DB USB (Hub #1)
(0:29:1) unknown card (0x0e11/0x00c5) using a Intel Corp. 82801DB USB (Hub #2)
(0:29:2) unknown card (0x0e11/0x00c5) using a Intel Corp. 82801DB USB (Hub #3)
(0:29:7) unknown card (0x0e11/0x00c5) using a Intel Corp. 82801DB USB2
(0:30:0) Intel Corp. 82801BA/CA/DB/EB PCI Bridge
(0:31:0) Intel Corp. 82801DB LPC Interface Controller
(0:31:1) unknown card (0x0e11/0x00c5) using a Intel Corp. 82801DB Ultra ATA Storage Controller
(0:31:5) unknown card (0x0e11/0x00c5) using a Intel Corp. 82801DB AC'97 Audio Controller
(5:8:0) unknown card (0x0e11/0x0091) using a Intel Corp. 82801BD PRO/100 VE (LOM) Ethernet Controller

When I run X -scanpci and ati9200 is pluged in I get this:
Probing for PCI devices (Bus:Device:Function)

(0:0:0) Intel Corp. 82845G/GL [Brookdale-G] Chipset Host Bridge
(0:1:0) Intel Corp. 82845G/GL [Brookdale-G] Chipset AGP Bridge
(0:29:0) unknown card (0x0e11/0x00c5) using a Intel Corp. 82801DB USB (Hub #1)
(0:29:1) unknown card (0x0e11/0x00c5) using a Intel Corp. 82801DB USB (Hub #2)
(0:29:2) unknown card (0x0e11/0x00c5) using a Intel Corp. 82801DB USB (Hub #3)
(0:29:7) unknown card (0x0e11/0x00c5) using a Intel Corp. 82801DB USB2
(0:30:0) Intel Corp. 82801BA/CA/DB/EB PCI Bridge
(0:31:0) Intel Corp. 82801DB LPC Interface Controller
(0:31:1) unknown card (0x0e11/0x00c5) using a Intel Corp. 82801DB Ultra ATA Storage Controller
(0:31:5) unknown card (0x0e11/0x00c5) using a Intel Corp. 82801DB AC'97 Audio Controller
(1:0:0) unknown card (0x174b/0x7c13) using a ATI Technologies Inc Radeon RV280 [Radeon 9200]
(1:0:1) unknown card (0x174b/0x7c12) using an unknown chip (DeviceId 0x5941) from ATI Technologies Inc
(5:8:0) unknown card (0x0e11/0x0091) using a Intel Corp. 82801BD PRO/100 VE (LOM) Ethernet Controller

Is it possible to run them both in dual config using xinerama ?

First off get the video drivers for both controllers so the Unknown part is known. In fact load all of the drivers...


But before that happens, what O/S are you using and what kernel is it on?


And then the xinerama answer is best answered by reading the howto's thoroughly.

http://wiki.linuxquestions.org/wiki/...Graphics_cards

http://www.linuxdocs.org/HOWTOs/Xinerama-HOWTO.html

EDIT: For the ATI driver I recommend DRI and not the Radeon driver that comes from ATI.com... http://dri.freedesktop.org

And then you will need to go to Intel.com for the other drivers if aren't in whatever O/S you are running.