cgminer is only finding single gpu

[FlappySocks]

cgminer is only finding single gpu

Code:

#:~$ aticonfig --lsa
* 0. 01:00.0 AMD Radeon HD 7900 Series
  1. 07:00.0 AMD Radeon HD 7900 Series

Code:

#:~$ cgminer -n
 [2013-06-15 15:35:36] CL Platform 0 vendor: Advanced Micro Devices, Inc.                    
 [2013-06-15 15:35:36] CL Platform 0 name: AMD Accelerated Parallel Processing                    
 [2013-06-15 15:35:36] CL Platform 0 version: OpenCL 1.2 AMD-APP (1113.2)                    
 [2013-06-15 15:35:36] Platform 0 devices: 1                    
 [2013-06-15 15:35:36]  0       Tahiti                    
 [2013-06-15 15:35:36] 1 GPU devices max detected  

From my research, it seems to be a known problem with OpenCL and Xinerama.  This is a 4 monitor workstation, and I need to have Xinerama switched on.

Most of the info I have found is old.  Are there any fixes?

[pvtbrutus]

Think you need to plug the second 7900 card with a dvi-dummy in order to enable it. Can you see the second card in amdcccle?

[pvtbrutus]

If you dont see the second card in amdcccle you could try:

Code:

sudo aticonfig --adapter=all --initial

This updates the X server settings file.

[FlappySocks]

thanks.

I have four monitors plugged in, and i already tried recreating the xorg config.

[pvtbrutus]

i more or less followed this guide to get it working:
https://docs.google.com/document/d/1Gw7YPYgMgNNU42skibULbJJUx_suP_CpjSEdSi8_z9U/edit

skip the driver part if you know your drivers are new enough.

[FlappySocks]

For now, I have switched Xinerama off and switched to using RandR.  This is not ideal, but better than keeping one gpu idle.