DIDEVICEINSTANCE guidInstance and guidProduct change on same device

Question

I am using DirectInput8 in a project at work that monitors various components of the pc. To monitor joysticks we use DirectInput8. The data is retrieved by enumerating all joysticks with DI8DEVCLASS_GAMECTRL as the type and DIEDFL_ATTACHEDONLY as a flag. Recently it was brought to my attention that we were having multiple joysticks showing up. First I looked at the xml file we store the components in between reboots. There were two entries for the joysticks, Logitech Extreme 3d pro, and each had a unique product guid. I backed the file up and removed it, effectively forcing a rescan of the machine next time the app started after I rebooted the machine. I was able to get the same problem to occur and logged out the guids and they are different for each. The system only has a single joystick plugged in however it plugs in through a usb hub. Is the hub affecting the guids I am seeing? I could also only get this to occur maybe 1 out of 5 attempts.

Example:

Joystick Product GUID: 3C6A972000000000504944564944 Joystick Instance GUID: 3C6A972097C11E3800144455354

Joystick Product GUID: DA83AFB000000000504944564944 Joystick Instance GUID: DA83AFB0D7B211E2800144455354

Answer 1

Had a similar issue... I just exported the DirectInput registry settings for the VID/PIDs I wanted to replicate GUIDs across machines.

So, in regedit navigate to:

[HKEY_CURRENT_USER\System\CurrentControlSet\Control\MediaProperties\PrivateProperties\DirectInput\VID_[Whatever]&PID_[Whatever]\

Right click, choose Export to create the .reg file, the move it to the machine you want and double click.