Invalid device error on second video card.

I’m getting an invalid device error when I try to create my command queue using my second video card. I have two Radeon HD 5800 series video cards (crossfire is off) and I only get this error with the second card. The program runs just fine on the first. I’ve looked into the AMD control center on my pc (windows 7 operating system) and it says the second cards adapter is disabled. How do I correct this? If it’s just a matter of enabling the card adapter how is that done? I’ve looked around a bit and haven’t had any luck with this.

First, check in Device Manager if the card is enabled, if not then enable it there. Additionally, you might need to extend your Windows desktop onto the second card - that does require connecting it to a display.

I figured out the issue. I was selecting the device correctly but I wasn’t passing the device id correctly to clCreateContext.