IOUSBHIDDriverDescriptorOverride

This OS X kernel extension provides a method for overriding a HID descriptor and ignoring the descriptor provided by the device. This is useful when the HID descriptor returned by a HID device is invalid or incorrect.

Supported Devices

Noppoo Choc Mini (1006:0022, 1007:8400)
Noppoo Choc Mid (04d9:1829)
Noppoo Choc Pro (04f3:5a5a)

Including the support from the original project for

Griffin PowerMate
Macally iShock

Noppoo

There are two problems when using a Noppoo keyboard on OS X

duplicate keypresses
modifier keys only working with some keys

The descriptors have an overlap by specifying both an immediate list of usages, and a range of usages. This causes OS X to send both usages when a key in the overlapping range is pressed. The solution used here is to split the item into two separate items: one for the immediate list and the other for the range. For the specifics of the descriptors and the changes to make them work, see the unencoded versions.

OS X has modifier state local to each keyboard; The Noppoo implements NKRO with two keyboard interfaces but only of which has the modifier state. This makes it impossible to use modifiers with any key on the non-modifier keyboard.

This project only fixes the problems caused by the descriptor. However installing KeyRemap4MacBook has the side effect of making modifier state global.

The combination of this extension and KeyRemap4MacBook should make the Noppoo keyboards behave as expected.

Installation

The Downloads section contains installer packages.

To build and install from source

# dependencies
gem install bundler
bundle install --without scan

# build
xcodebuild
sudo cp -r build/Release/IOUSBHIDDriverDescriptorOverride.kext \
    /System/Library/Extensions
sudo kextutil \
    /System/Library/Extensions/IOUSBHIDDriverDescriptorOverride.kext

Unsupported Devices

The Noppoo devices have a range of identifiers and descriptors. If a device is not supported, there is an experimental feature that will generate the Info.plist section for any connected device that has the Noppoo-style overlapping descriptors.

# dependencies
brew install libusb
bundle install --without ""

# build
rake scan

A file for your keyboard will be generated in the descriptors directory. Follow the instructions in the previous section to install the resulting module.

This feature is experimental, but works for limited test cases. If the resulting .kext works with your keyboard, submit a pull request with the new descriptors, otherwise open an issue with the new descriptors.

Troubleshooting

Ensure the kext is loaded

Use kextstat to list currently loaded modules. The module named IOUSBHIDDriverDescriptorOverride must be present.

$ kextstat | grep IOUSBHIDDriverDescriptorOverride
   59    0 0xffffff7f80bc6000 0x2000     0x2000
   ryangoulden.driver.IOUSBHIDDriverDescriptorOverride (1) <58 25 4 3>

If the driver is not loaded, use kextutil on the kext.

$ sudo kextutil -v /System/Library/Extensions/IOUSBHIDDriverDescriptorOverride.kext

Ensure the kext is being used

Use ioreg to list system resources. For the Noppoo keyboards, there should be two instances of IOUSBHIDDriverDescriptorOverride.

$ ioreg -b -f | grep IOUSBHIDDriverDescriptorOverride
    | |   |   | | +-o IOUSBHIDDriverDescriptorOverride  <class IOUSBHIDDriverDescriptorOverride, id 0x100000273, registered, matched, active, busy 0 (125 ms), retain 10>
    | |   |   | | +-o IOUSBHIDDriverDescriptorOverride  <class IOUSBHIDDriverDescriptorOverride, id 0x10000027b, registered, matched, active, busy 0 (101 ms), retain 10>

If the driver is not being used, make sure your device was inserted after the driver was loaded. The kext should be loaded early during boot, so rebooting should be sufficient for the driver to be selected for the device. Otherwise, check if your device is supported.

For a list of supported devices examine Info.plist

$ plutil -p /System/Library/Extensions/IOUSBHIDDriverDescriptorOverride.kext/Contents/Info.plist
...
    "Noppoo Choc Mini (primary)" => {
      "bInterfaceNumber" => 0
      "CFBundleIdentifier" => "ryangoulden.driver.IOUSBHIDDriverDescriptorOverride"
      "IOProviderClass" => "IOUSBInterface"
      "HIDDefaultBehavior" => ""
      "IOClass" => "IOUSBHIDDriverDescriptorOverride"
      "ReportDescriptorOverride" => <05010906 a1010508 19012903 15002501 75019503 91029505 91010507 19e029e7 95088102 19042928 95258102 094f0950 092b092c 09510952 09539507 81021959 2964950c 8102c0>
      "bConfigurationValue" => 1
      "idProduct" => 34
      "bcdDevice" => 320
      "idVendor" => 4102
    }
...

To see the properties attached USB devices, use ioreg

$ ioreg -p IOUSB -c IOUSBDevice | grep -e class -e idVendor -e idProduct -e bcdDevice
...
      +-o USB Keyboard @1d120000  <class IOUSBDevice, id 0x10000026d, registered, matched, active, busy 0 (312 ms), retain 16>
      |     "idProduct" = 34
      |     "bcdDevice" = 320
      |     "idVendor" = 4102
...

Devices not in the Info.plist are not supported by this project. If you think a device can be fixed by overriding the HID descriptor, please open a ticket with information about the device.

Other

If the driver is loaded and being used for your device, but the device is not behaving correctly, please open a ticket.

Acknowledgements

This project is a fork of the Google Code project of the same name, and has been extended to handle issues with the Noppoo Choc Mini and Noppoo Choc Pro.

ImTech / iousbhiddriver-descriptor-override