The Tesla P6 does not appear in the list of Cuda-enabled products at CUDA GPUs - Compute Capability | NVIDIA Developer.
What software is available for GPU-accelerated computations if Cuda is not available?
https://www.nvidia.com/download/driverResults.aspx/132546/en-us
Supported Products
P-Series:
Tesla P100, Tesla P40, Tesla P6, Tesla P4
I would assume P6 gets the same support as all the other Tesla P series cards, including CUDA acceleration.
That an older list of CUDA enabled products has not been updated yet with a new GPU model may just be an oversight.
NVIDIA’s various support lists lag reality quite often, as messages in these forums demonstrate. All GPUs NVIDIA has produced in the past ten years are CUDA capable, but NVIDIA removes software support for outdated hardware in steps. Current versions of CUDA (9.2 / 10) support all GPUs with compute capability 3.0 (corresponds to the Kepler architecture introduced ~2012) and higher.