WDDM and TCC mode cannot coexist?

There are two cards installed in my system, one is 1080GTX the other is Titan X pascal, with cuda 8.0 and driver 376.33 and OS being Windows 10 pro 64bit.

1080GTX is the card used to display, whilst titan x is used purely for computation.

The problem I get is: when both cards are set to WDDM mode, cuda programs work well, however if I set titan x to TCC mode and leave 1080GTX as WDDM, and if I want to use both GPUs for computation, then the programs will crash at calling cudaGetDeviceProp or cudaSetDevice through access violations.

Is this a bug or some known limition of TCC/WDDM?

I have run into this issue, but not when I mix Maxwell with Pascal.

On my Windows 7 x64 system I currently have a GTX 1080 in slot 0 and a Maxwell Titan X in slot 1. I put the Maxwell Titan X in TCC mode, while the GTX 1080 uses WDDM.

In a multi-GPU application I have no problem accessing both in course of the application. But when I tried the same configuration with a Pascal Titan X and the GTX 1080 I got the same crash as you in that same application, right when I would call ‘cudaSetDevice’.

At the time I created a post and was told that I had an early driver and the problem would probably be fixed in later versions. I switched out the Pascal Titan X and re-installed the Maxwell Titan X, which still works.

I should have filed a bug, but did not get around to it. I recommend you file a bug, as this is not just your system rather appears to be a larger issues which NVIDIA still has not fixed. A bug report will work, as I have had success with filing such reports in the past.

Thanks for the reply, now I know it is indeed a bug, I just reported it, hope they can fix it soon.