Gamecube controller adapter and Linux

[ttshaw1]

I have a Mayflash Gamecube controller adapter that I'm trying to get to work with Dolphin (and retroarch) on a new computer. I've tried three different approaches, and have run into a snag on each one.

1. Following this guide: https://wiki.dolphin-emu.org/index.php?t...phin#Linux
   I don't have the file /etc/udev/rules.d/51-gcadapter.rules on a fresh install, so this guide is already off the rails in my case.
   
2. Compiling and using this driver: https://github.com/ToadKing/wii-u-gc-adapter
   Dolphin detects the controller and the inputs mostly work, but the analog stick has ludicrous drift to the bottom right, requiring a dead zone setting of 50+, which obviously makes using the stick pretty much impossible.
   
3. Flipping the switch on the adapter to PC and letting generic or Dolphin-packaged drivers take care of it
   This works fine on another computer running Linux Mint 19 Cinnamon with Dolphin 5.0, but for some reason this new computer detects the adapter as a Pokken controller, which makes the analog stick useless
   

I know the hardware is fine from trying it on my other computer. I don't know where to begin troubleshooting this, and I'd greatly appreciate any help.

[JosJuice]

Following this guide: https://wiki.dolphin-emu.org/index.php?t...phin#Linux
I don't have the file /etc/udev/rules.d/51-gcadapter.rules on a fresh install, so this guide is already off the rails in my case.

In that case, create the file.

[Chuckaluphagus]

Flipping the switch on the adapter to PC and letting generic or Dolphin-packaged drivers take care of it
This works fine on another computer running Linux Mint 19 Cinnamon with Dolphin 5.0, but for some reason this new computer detects the adapter as a Pokken controller, which makes the analog stick useless

I have no idea what Pokken is, but the solution for this specific problem was posted in a different thread recently.

I'm having a different issue with the same Mayflash adapter: I created the udev rule, and now Dolphin recognizes the adapter as a GameCube Adapter for Wii U.  But, it then gives me the error message of "Error Opening Adapter: Input/Output Error".

Anyone have any idea how to troubleshoot that?

The adapter works fine when switched to "PC" mode, and with the controllers set to "Standard Controller" in the Dolphin configuration, so this is mostly curiosity.