4 Replies Latest reply on Feb 4, 2014 5:37 AM by reapster

    Xinerama stops OpenCL seeing my two GPUs

    logicethos

      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.