Does the steam controller work on Stadia at the moment?
Yes, there was a post about it on Reddit earlier today. At $5, it's a great deal.
(for posterity) I believe this is the link: https://www.reddit.com/r/Stadia/comments/fyk7nj/stadia_with_steam_controller_ds4_and_nintendo_pro/
I imagine the only thing you would have to do is add chrome to steam and launch it through steam. You could also probably use the game links. This is to get full functional there may be other options and just thoughts as I haven't used my steam controller in over a year.
I added Chrome to my Steam library and launched it via Big Picture. This does not allow me to use the Steam controller on Stadia. I found that some button presses were received, but I have no way on the Stadia side to edit the inputs and a lot were incorrect or unresponsive. I also found that having Big Picture running while running a game (Samurai Shodown) produced a significant amount of lag in just navigating Big Picture menus and Windows. Maybe it's possible to use Steam's controller configuration menu to make changes but I was unable to access the controller configuration menu I usually see when in-game on Steam Big Picture.
I noticed that Stadia's FAQ does not include the Steam controller on its list of supported controllers and I would very much like to request that it be added.
The main issue is that Steam themselves don't want their controller to function outside of Steam. Considering they just discontinued it, I doubt they'll ever make their controller friendly with outside software.
same here, also doesnt work. only seems to pick up the X button and the left joystick.
To make Steam Controller working on Stadia you must download and install GloSC (https://alia5.github.io/GloSC/). Once installed, open it and add Chrome. It worked for me.
If there's anyone out there like me on Linux wanting to use their Steam Controller with Stadia, I've had great success with sc-controller (https://github.com/kozec/sc-controller). The AUR package (https://aur.archlinux.org/packages/sc-controller-git/) for Arch Linux uses the Python 3 fork (https://github.com/Ryochan7/sc-controller), and works great. The remapping you can do with this (like adding a trigger-able gyro mouse) makes this very nice. I'm interested to see how the work from these projects may be repurposed for the Steam Deck when it arrives.