Connecting multiple Xbox One S controllers wirelessly with outdated controller firmware causes system instability

[bitrot-alpha]

Your system information

• Steam client version: 1733265492
• SteamOS version: 3.6.20
• Opted into Steam client beta?: No
• Opted into SteamOS beta?: No
• Have you checked for updates in Settings > System?: Yes
• Device Model: Steam Deck LCD 512GB

Please describe your issue in as much detail as possible:

Describe what you expected should happen and what did happen.

Attempted to connect two Xbox One S (Bluetooth enabled) controllers via Bluetooth. I expected they would "just work."

What actually happened was the second controller would act like it was paired, but no buttons or sticks would work. The second controller also did not show up in the SteamOS controller settings. It did show as paired in the bluetooth menu.

I have since updated the controllers' firmware with the Windows 10 Xbox Accessories application. Once updated, both controllers showed up in the Controllers menu as "Xbox One S Controller"

I'm not sure if this is an upstream issue as I have no idea what Xbox controller driver SteamOS uses. I can't provide info as to what version the old firnwares were, but one of the controllers appears to be a launch edition Xbox One S controller, and it may have been on the factory firmware. This older controller is the Model 1708 according to the sticker on the back, which Wikipedia says is the first Bluetooth Xbox One controller.

Steps for reproducing this issue:

1. Connect multiple Xbox One S controllers with outdated firmware wirelessly
2. Only one controller functions
3. Observe in the controllers menu that only one controller shows up as "Xbox Controller" aside from the built in Steam Controller.
4. Attempting to reconnect the second controller may cause the Steam Deck to reboot or crash the Bluetooth stack

The remedy for the end user is to update the controller firmware with the Windows 10 "Xbox Accessories" app. If your system has no TPM (you get the error "Your OS is out of date" or similar) use the older version of the application, 2402.2402.12001.0, which is available from sites such as Uptodown.