So I've been looking all over the internet to see how to fix this issue, when I stumbled upon a really old forum thread. This problem has apparently been going on for 2 years with no answer in site. I'm not sure if something has been fixed and I can't find the right info but here is the thread. The comment that pretty much explains the issue is this.
"actem
It shows up as 057E 0337, and Dolphin says that it detects a GameCube adapter (yay!), but then the controller doesn't actually do anything in-game.
Anyway, thanks for helping!
EDIT: So Dolphin recognizes the adapter, but once I start a game Dolphin stops detecting it. I think that's the reason for the problem, but I don't know how to fix it."
Link: https://forums.dolphin-emu.org/Thread-gamecube-adapter-not-working
I'm having this exact same issue years later. Has there been any focus or news on this?
"actem
It shows up as 057E 0337, and Dolphin says that it detects a GameCube adapter (yay!), but then the controller doesn't actually do anything in-game.
Anyway, thanks for helping!
EDIT: So Dolphin recognizes the adapter, but once I start a game Dolphin stops detecting it. I think that's the reason for the problem, but I don't know how to fix it."
Link: https://forums.dolphin-emu.org/Thread-gamecube-adapter-not-working
I'm having this exact same issue years later. Has there been any focus or news on this?