hid_enumerate fails with "Failed to get size of HID device interface list" when running a windows app on Steam Deck

[rafael-f]

As title says I'm trying to use hidapi to enumerate controllers on a game running on steamdeck.

It works when running on windows but when the game is running on steamdeck I get that error:

"Failed to get size of HID device interface list"

Is there anything I should be doing? Is it just not compatible?

[Youw]

The error you get indicates that CM_Get_Device_Interface_List_SizeW fails here.
Unfortunately the error-code is not being logged, so if you could modify and the library to log the cr as well - that might give a little more to reason what is going on there.

If I where to guess - the application from the context you run it either don't have access to HID devices (or any direct access to similar devices) at all, or it has something to do with CfgMgr32 API.
You may try to use HIDAPI v0.11.1 (or older) since that one uses SetupAPI instead of CfgMgr32.

[rafael-f]

Wow thank you VERY MUCH, using v 0.11.0 worked instantly, seems the reason really is CfgMgr32.

[Youw]

Very interesting. I still would be interested to know why CfgMgr32 API fails on Steam Deck...