I'm not keeping mum about anything. I've tweeted this previously too.
ALL of our SFV products work with PC (d-input) as do all PS4 controllers, since we use the same IC solution that licensed PS4 products use.
However, Capcom's Street Fighter V on PC only supports x-input at this time --
it is being updated (from what I've been told), but at this moment, only x-input will work.
What does this mean? Capcom addressed it on their Steam FAQ:
http://steamcommunity.com/app/310950/discussions/0/483368526574345402/
We are also working on firmware updates to our products to allow an x-input mode. However, I don't have a solid date on when that will be ready.