RetroArch cannot configure Nintendo 64 Hyperkin Adapter

Description

I have recently replaced my USB N64 controller with an adapter that connects an ordinary N64 controller to a PC's USB receptacle, because the previous USB controller had a poorly functioning control stick. So I decided to try out the adapter to see if it works on RetroArch.

Expected behavior

I was hoping RetroArch would be capable of reading the adapter well, and it would configure the controller attached to it just like my previous USB controller.

Actual behavior

When connecting an N64 controller to the adapter, and I press either: START, B, R, or any of the C buttons when trying to configure them, I get NO response from RetroArch, which seemed strange, because outside the app, all the buttons work perfectly.

Also, whenever I boot up RetroArch with the adapter and controller connected, I get a notification like, "Hyperkin Adapter not configured, using fallback".

Finally, when I try to boot up a ROM, the port I'm using is disconnected, and I get trapped in a game, until I put the Steam Deck on sleep, and then I turn it back on to get to the menu.

• OS: Steam Deck (Desktop mode)

Start by reproducing the controller configuration and ROM-launch behavior on a Steam Deck with the Hyperkin N64 adapter connected. Trace the fallback notification, ignored button presses, and port disconnection; done means the adapter configures its buttons and the selected port remains connected when a ROM starts.