hi,
i am trying to use opencl with multiple GPU devices on linux, but i am only able to work with the first GPU-device within the system - and the CPU, but thats not my problem, i want to use multiple GPU devices. i am using somewhat older cards - i am doing software development for academic purposes, not for real hpc on this system ... so no money available to buy 2 brandnew 79x0 devices 
... 😕
the devices are two 5750, one 5770 an one 6570 card.
regardless which pair of these three cards i try to use, i always see only the first device within the system - asrock 870 socket am3 mainboard with 2 pci-e slots.
to test/access these cards i use a small mockup example in c++ - via the fglrx-driver/amdapp sdk - and java (jocl.org).
* my general setting: debian squeeze with backports-org 3.2 kernel
amd-app sdk 2.7
fglrx-12.4 (the recommended vor sdk 2.7) and 12.8 (the current one
* xorg.conf: fresh configuration generated with
aticonfig --adapter=0,1 --initial
* i use opencl version 1.2
* the cards are visible to the system - there are 2 working monitors, one connected to each of the cards and for example the fglrxinfo shows active opengl for both cards ... in this case one 5750 and the 6570 device:
thorp:~$ fglrxinfo
display: :0.0 screen: 0
OpenGL vendor string: Advanced Micro Devices, Inc.
OpenGL renderer string: ATI Radeon HD 5700 Series
OpenGL version string: 4.2.11762 Compatibility Profile Context
display: :0.0 screen: 1
OpenGL vendor string: Advanced Micro Devices, Inc.
OpenGL renderer string: AMD Radeon HD 6570
OpenGL version string: 4.2.11762 Compatibility Profile Context
are there any known problems with opencl and these older cards? does it make sense to buy newer ones or is there a problem with the relative old debian squeeze system? should i use a current ubuntu version for example?
i am thankfull for any hint or link - if this is a rtfm question: sorry, but i am searching the net for answers to this problem since a few days, so i think it shouldn't be a trivial question.
cheers
v.
hi,
yes - DISPLAY=:0.0 - i am working on this system within X.
cheers
v.
hey,
woops: you are right - now i am able to use the second GPU-device.
sorry for my "noob" question - i am working with opencl since a rather long time, but always only with one device and therefore never encounterd this problem
cheers
v.
