IOServiceOpen Keeps Returning kIOReturnUnsupported

I have a custom HID device that works on Windows totally fine with the default HID driver. The HID device knows how to accept string commands to control it and respond accordingly. I am trying to control it on Mac using IOKit.

I am able to get the io_service_t reference to the IOHIDInterface for the device from the I/ORegistery. I use this to instantiate a class to represent the device. But when I try to establish a connection to the service, I keep getting -536870201 which corresponds to kIOReturnUnsupported. I'm not entirely sure what I am doing wrong here and I wasn't able to find anything online that could really help.

Up vote post of CanfieldADemerjian Down vote post of CanfieldADemerjian
372 views
Posted by
CanfieldADemerjian
Reply
Add a Comment

Replies

You can not open a user client for an IOHIDInterface. You should instead locate the io_service_t for the IOHIDDevice service (the provider of the IOHIDInterface) and open a user client on it. For HID devices, our recommendation is to use the IOHIDDevice APIs rather than the lower level IOKit userspace primitives (like IOServiceOpen).

Posted by
Justin
Post not yet marked as solved Up vote reply of Justin Down vote reply of Justin

  • UPDATE: I was able to control my custom HID device using IOHIDManager, but thank you for the help!

    —
    CanfieldADemerjian
Add a Comment