[Wii U] No controller rumble

First and foremost consider this:

• Only RetroArch bugs should be filed here. Not core bugs or game bugs
• This is not a forum or a help section, this is strictly developer oriented

Description

Wii U controller rumble is either not supported or broken. Attempting to map a memory address to rumble the GamePad or other controllers performs no action.

Expected behavior

I configure a cheat file which conditions specific memory addresses to vibrate the controllers under certain circumstances. The controller(s) should vibrate under these conditions.

Actual behavior

The controller(s) do not vibrate when the conditions are met. I have tested this on both the Wii U GamePad and Wii U Pro Controllers, and it happens on every game and cheat config I use. I've tested it in the Snes9x and mGBA cores.

Steps to reproduce the bug

1. Start RetroArch on Wii U through Homebrew Launcher and start a game
2. Load a cheat file with rumble support
3. Attempt to trigger the rumble

Bisect Results

I am unsure as to whether or not rumble was ever supported with RetroArch for Wii U.

Version/Commit

You can find this information under Information/System Information

• RetroArch: 1.10.3/dc2f6da

Environment information

• OS: WiiU

Begin by tracing Wii U controller rumble handling and the cheat-trigger path in RetroArch, comparing behavior with the Snes9x and mGBA cores. No source file or test is identified in the issue; done means a Wii U GamePad and Pro Controller vibrate when the configured cheat conditions are met.