CGMiner recognizes all video cards, but implements only one; help requested.

I haven't had a reason to post here on bitcointalk before so I suppose I have to make my request for assistance in the newbie forum first.

I have a problem (ubuntu 12.04) where my AMD driver and CGMiner recognizes all of my video cards, but only implements the first one. when I try to mine using more than one card, the other cards will remain idle as the load is spread across what cgminer outputs as "GPU 0, GPU 1 and GPU 2" even though it is only using my 7950. Here's my console output, note the device names. 7800 series is pitcairn, not tahiti.

Code:

adam@adam-TA870U3:~/c$ ./cgminer -V
cgminer 3.3.1
adam@adam-TA870U3:~/c$ cd /home/adam/c
adam@adam-TA870U3:~/c$ aticonfig --lsa
* 0. 01:00.0 AMD Radeon HD 7900 Series 
  1. 02:00.0 AMD Radeon HD 7800 Series 
  2. 03:00.0 AMD Radeon HD 7800 Series 

* - Default adapter
adam@adam-TA870U3:~/c$ aticonfig --adapter=all --odgt

Adapter 0 - AMD Radeon HD 7900 Series 
            Sensor 0: Temperature - 35.00 C

Adapter 1 - AMD Radeon HD 7800 Series 
            Sensor 0: Temperature - 33.00 C

Adapter 2 - AMD Radeon HD 7800 Series 
            Sensor 0: Temperature - 32.00 C
adam@adam-TA870U3:~/c$ export DISPLAY=:0
adam@adam-TA870U3:~/c$ export GPU_USE_SYNC_OBJECTS=1
adam@adam-TA870U3:~/c$ ./cgminer -n
 [2013-06-27 02:56:45] CL Platform 0 vendor: Advanced Micro Devices, Inc.                    
 [2013-06-27 02:56:45] CL Platform 0 name: AMD Accelerated Parallel Processing                    
 [2013-06-27 02:56:45] CL Platform 0 version: OpenCL 1.2 AMD-APP (1016.4)                    
 [2013-06-27 02:56:45] Platform 0 devices: 3                    
 [2013-06-27 02:56:45] 	0	Tahiti                    
 [2013-06-27 02:56:45] 	1	Tahiti                    
 [2013-06-27 02:56:45] 	2	Tahiti                    
 [2013-06-27 02:56:45] GPU 0 AMD Radeon HD 7900 Series  hardware monitoring enabled                    
 [2013-06-27 02:56:45] GPU 1 AMD Radeon HD 7800 Series  hardware monitoring enabled                    
 [2013-06-27 02:56:45] GPU 2 AMD Radeon HD 7800 Series  hardware monitoring enabled                    
 [2013-06-27 02:56:45] 3 GPU devices max detected                    
 [2013-06-27 02:56:45] USB all: found 12 devices - listing known devices                    
 [2013-06-27 02:56:45] No known USB devices                    
adam@adam-TA870U3:~/c$

as you can see, it lists my devices as tahiti, even though device 1 and 2 should read "pitcairn". I have only one display.

I know this problem is solvable, since I read from another poster that he/she fixed this problem (they had the same problem, https://bitcointalk.org/index.php?topic=226423.0) but there was no solution posted.

any help would be appreciated. I look forward to posting this in a more pertinent place.