On a similar experience, I use moonlight on my Android TV to stream video games from my computer in another room. I use my own fork from an unmerged PR which enables me to use an Xbox One Wireless adapter so I can play with my pad wirelessly. These pads have a 3.5mm jack on them which on Windows and Linux enables me to route audio from the game to headphones connected to the pad. Moonlight and the xow driver it bundled, was nowhere near being able to provide this as a feature.
After about 5 hours, feeding it the GIP spec, an export of sniffed usb traffic from Windows, prior art (xone driver for linux), and giving Claude connectivity to my Shield via adb, I had it working. This continuously blows my mind that I dont have to beg a developer on Github to do it for me.
Claude could do it for me for $20.
I have another controller-related anecdote.
I have a Razer Wolverine Xbox controller that has extra back paddle buttons. The controller doesn't expose the paddles directly to PC's over USB. You have to use button remapping on the controller to map them to 'real' Xbox buttons for the PC to see them. But I wanted to use the back paddle buttons on Steam as separate controls.
So I downloaded the latest firmware update off the internet (because what device doesn't have firmware updates these days), installed Ghidra and an MCP server for it, and told Sol to look for how I can expose these extra buttons to a PC host. Maybe we could write a firmware patch?
Turns out the controller already has a special mode to expose those buttons, possibly as a hardware test. But it was enough to write a Linux driver to put the controller into that mode, and a little bit of extra driver code to map the paddles to a Linux controller button, and voila. Paddles working in Steam.
And it only took a few hours to do, too. I spent more time making an open source repository out of the concept than I spent making it work.