Ubuntu Xinerama + mining

Hi
is there really no way to have Xinerama AND all GPU's active mining like here described?

http://whythiserror.blogspot.co.at/2013/06/adl-detected-more-less-devices-gpus.html

if Xinerama is on and I use 2 Monitors there is only one GPU active for mining

bfgminer and cgminer says

Code:

CL Platform 0 vendor: Advanced Micro Devices, Inc.                    
 [2013-09-08 20:08:53] CL Platform 0 name: AMD Accelerated Parallel Processing                    
 [2013-09-08 20:08:53] CL Platform 0 version: OpenCL 1.2 AMD-APP (1307.1)                    
 [2013-09-08 20:08:53] Platform 0 devices: 1                    
 [2013-09-08 20:08:53] 	0	Cypress                    
 [2013-09-08 20:08:53] ADL found more devices than opencl!                    
 [2013-09-08 20:08:53] There is possibly at least one GPU that doesn't support OpenCL                    
 [2013-09-08 20:08:53] Use the gpu map feature to reliably map OpenCL to ADL                    
 [2013-09-08 20:08:53] WARNING: Number of OpenCL and ADL devices did not match!                    
 [2013-09-08 20:08:53] Hardware monitoring may NOT match up with devices!                    
 [2013-09-08 20:08:53] GPU 0 ATI Radeon HD 5800 Series hardware monitoring enabled                    
 [2013-09-08 20:08:53] 1 GPU devices max detected

if Xinerama is off two GPU's are active for mining but I have only clone desktop on both Monitors

TIA