Operating system: windows 10 1903
Graphics card: 2 * GEFORCE GTX 1080ti NVIDIA 441.87
Broken: 2.81a and same with 2.82 daily build ( Jan 22th 2020)
Short description of error
I'm using AMD 3950x and 2 GTX 1080tis.
The render engine is cycles. When 3D view is processing rendering, simply press F12 to render.
After the render finished, The 3D view port shows canceled on the top left side, the view port render failed.
And if you press F12 to render again. the blender render view shows CUDA error at cuCtxCreate : render failed.
In the render properties panel, in this case, sometimes the rendering device GPU is greyed out, can not be choosen.
I can only choose CPU as render device, and CPU workes fine.
Reboot blender the problem will be solved, but if I try F12 rendering while 3D view port is rendering, the issue comes again.
I tested this process with my intel i7 6800K and single GTX 1080 machine. It works totally fine.
But with 2 1080tis, it happens at nearly 100% chance no matter I choose CPU+GPU or single GPU. Sometimes blender crashes instantly.
I asked my friend who is using AMD 3700x and Nvidia 2070 to follow my step to test. He don't have the same issue. 3700x and 2070 works fine.
So I tested to render with one GPU and then another. The result is the first slot GPU works fine, but the second slot GPU has this issue. When rendering with the second slot GPU, the render cannot finish and blender not responding.
Exact steps for others to reproduce the error
First It happens only on 1 GPU. Another works fine.
Start blender, switch render to cycles and device to GPU compute.
Switch 3D view port to rendered. Before path tracing finishes, press F12 to render.