4 Replies Latest reply on Nov 2, 2012 10:43 PM by sayantandatta

    Catalyst/AMD APP not detecting second discrete GPU.


      Hello everyone,


      I have the following sytem configuration right now:

      Motherboard: ASUS P8P67

      PCIE x16(BLUE)  : ASUS Radeon HD 7970

      PCIE  x4(BLACK) : Sapphire Radeon HD 4890


      OS: Ubuntu 12.04(x64), Catalyst ver:12.4 ,   AMD APP 2.6

      OS: Windows 7(x64)   , Catalyst ver 12.10,  AMD APP 2.5


      Both the OS detect  the second card in hardware information but catalyst/APP doesn't detect the second GPU in either OS. 

      In ubuntu I checked using lspci command.

      In windows I checked using hardware information GUI.


      When my monitor is attached to the 7970 and I get output on the screen. However when I connect the monitor to 4890 while the 7970 is still in the x16 slot I don't get any output on screen.


      How do I use my 4890 for opencl only and the 7970 for both opencl and display ?


      It would be greatly helpful if anyone can provide a step by step tutorial for both OSes. 




        • Re: Catalyst/AMD APP not detecting second discrete GPU.

          Under linux you need to make sure that there is a device section for each gpu in your /etc/xorg.conf. An easy way to achieve is with the aticonfig utility:


          aticonfig --initial -f --adapter=all


          should do the trick.


          You can check which devices are being detected by the opencl runtime by running the clinfo tool.


          Note that the 4890 is fairly old and does not fully support OpenCL. I'm not sure what functionality is missing (I believe it has limited support for __local memory). Also in terms of performance it may not be worth using it in addition to the 7970.

          1 of 1 people found this helpful
            • Re: Catalyst/AMD APP not detecting second discrete GPU.

              Did that.


              Now the catalyst has control over both the GPUs.


              sayantan@Eden:/usr/bin$ aticonfig --adapter=1 --odgc

              Adapter 1 - ATI Radeon HD 4800 Series          

                                              Core (MHz)    Memory (MHz)

                        Current Clocks :    240           975

                           Current Peak :    850           975

                Configurable Peak Range : [500-1000]     [975-1200]

                               GPU load :    0%


              sayantan@Eden:/usr/bin$ aticonfig --adapter=0 --odgc

              Adapter 0 - AMD Radeon HD 7900 Series

                                          Core (MHz)    Memory (MHz)

                         Current Clocks :    300           150

                           Current Peak :    925           1375

                Configurable Peak Range : [300-1125]     [150-1575]

                               GPU load :    0%


              However clinfo does not show the two GPUs. It only detects Tahiti. I did a reinstall(installed again without un-installing first) of APP 2.6 but the probelem persist.


              Any suggestions?