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Xinerama stops OpenCL seeing my two GPUs

Question asked by logicethos on Jun 16, 2013
Latest reply on Jan 30, 2014 by reapster

I have two 7950 in my Linux PC.

 

#:~$ aticonfig --lsa

 

* 0. 01:00.0 AMD Radeon HD 7900 Series

   1. 07:00.0 AMD Radeon HD 7900 Series

 

If I switch Xinerama on, then OpenCL can only see 1 gpu.  Here is what cgminer says:

 

#:~$ 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

 

Switch Xinerama Off, and it can see the two gpu's.  The dev for cgminer says it's because Xinerama mode creates one virtual screen, and OpenCL for some reason looks at the "Screen" rather than "Device" configuration.

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