What is VoodooSMBus?

VoodooSMBus solves two related problems:

1. VoodooSMBus is a project that provides a kernel extension (driver) for macOS that adds support for the SMBus capabilities of Intel I/O Controller Hubs (ICH), also called i801 SMBus.
2. VoodooSMBus also contains a slave device driver for the ELAN Touchpad device found on the SMBus of some Thinkpad models (T480s, L380, P52) making it possible to use multitouch gestures efficiently.

This project is heavily inspired by https://github.com/alexandred/VoodooI2C and a complete reimplementation of the ideas in https://github.com/gokula/ELANSMBus. Multitouch support is made possible by the implementation VoodooI2C.

VoodooSMBus ports the i2c-i801¹ driver and the elan_i2c_smbus² from linux to macOS.

In the future we might want to split up the project, similar as it has been done in VoodooI2C, into a controller kext and kexts for the slave device drivers.

Installation

• Add VoodooPS2Controller.kext
• Add the patch in config.plist.patch, so VoodooPS2Controller does not attach itself to the PS2 interface of the touchpad
• Delete VoodooPS2Controller.kext/Contents/PlugIns/VoodooPS2Mouse.kext, otherwise the touchpad will not work after sleep
• Add the four patches found here https://github.com/leo-labs/macOS-ThinkPad-T480s/blob/master/EFI/CLOVER/config.example.plist#L436-L467 and https://github.com/leo-labs/macOS-ThinkPad-T480s/blob/master/EFI/CLOVER/config.example.plist#L500-L535 to supress loading of those kexts
• Config bootloader
  • Clover: Disable FixSBUS under ACPI->DSDT->Fixes in your Config.plist
  • OpenCore: Make sure you don't have SSDT-SBUS-MCHC or SSDT-SBUS
• Install this kext

Configuration

Some settings can be configured in the Configuration dictionary in Info.plist:

• DisableWhileTyping Enable disable while typing functionality. After a key press the touchpad is deactivated for a certain amount of time, specified by
• DisableWhileTypingTimeoutMs The amount of time in milliseconds that touch input is ignored after typing
• DisableWhileTrackpoint Disables the touchpad when the trackpoint is in use.
• DisableWhileTrackpointTimeoutMs The amount of time in milliseconds that touch input is ignored after trackpoint usage
• IgnoreSetTouchpadStatus Ignores messages from the keyboard driver to disable the touchpad. If not ignored, the touchpad can usually be toggled with the PrtSc key.

Current Status

Currently the following Intel I/O Controller Hubs are supported and tested:

Name	Id	Device
Sunrise Point-LP (PCH)	pci8086,9d23	Thinkpad T480s, L380
Cannon Lake-H (PCH)	pci8086,a323	Thinkpad P52, X1 Extreme

It should be trivial to add support for all controllers listed in ¹.

Trackpoint support is implemented, make sure to activate the trackpoint in BIOS.

For a list of planned features, see https://github.com/leo-labs/VoodooSMBus/labels/enhancement

Supported Gestures

For supported gestures please see https://voodooi2c.github.io/#Supported%20Gestures/Supported%20Gestures

VoodooSMBus does not load

• Check IORegistryExplorer and make sure AppleSMBUSControllerPCI does not attach. If it does:
  • Clover: Check that you don't have FixSBUS enabled in your Config.plist.
  • OpenCore/Clover: Make sure you don't have an SSDT which adds properties to SBUS
• If VoodooSMBus still does not attach after getting AppleSMBusController out of the way, then you may need to add your own SMBus controller device ID to the Info.plist.
  • Finding your device ID:
    • Windows:
      • Under Device Manager, look for your SMBus controller. For Synaptic devices, it may appear as Synaptics SMBus Driver.
      • Once you've found the device, look at it's properties, go into details and select "Hardware Ids". VEN_xxxx is the vendor id, and DEV_xxxx is the device id.
    • MacOS:
      • Open IORegistryEditor, and find the SBUS device.
      • Look on the right hand side. You should see Vendor-id and device-id. You should only take the first two bytes of each and swap them. For example, the first two bytes of 86 80 00 00 is 86 80. If we swap the position of these, it should be 80 86.
  • Adding Device id:
    • Go into VoodooSMBus.kext (may need to right click and select "Show Package Contents" on macOS), and find Info.plist
    • In the Info.plist, find "IOKitPersonalities", then VoodooSMBusControllerDriver.
    • Under IOPCIMatch, add the device id to the end of the string. The format is 0xYYYYXXXX, where YYYY is the DEVICE id and XXXX is the VENDOR id. Your vendor ID should be 8086, so the format really becomes 0xYYYY8086.

If your device is compatible and adding the device-id worked, please submit a Pull Request or issue!

Acknowledgements

Thanks to:

• @gokula for the first version of an SMBus driver for the touchpad https://github.com/gokula/ELANSMBus
• @alexandred, @coolstar, @kprinssu (& others) for the development of the VoodooI2C kernel extension, VoodooI2CELAN satellite and the native gestures implementation. https://github.com/alexandred/VoodooI2C & https://github.com/kprinssu/VoodooI2CELAN/tree/master
• @rehabman for the VoodooPS2 kernel extension and all other stuff he makes. https://github.com/RehabMan/OS-X-Voodoo-PS2-Controller
• @dukzcry for his Intel ICH SMBus controller which was of great help in the driver development. https://github.com/dukzcry/osx-goodies/tree/master/ic
• all linux kernel driver developers (especially the ones responsible for the i2c/smbus implementation and the elan i2c/smbus driver)

Footnotes

1: https://github.com/torvalds/linux/blob/master/drivers/i2c/busses/i2c-i801.c

2: https://github.com/torvalds/linux/blob/master/drivers/input/mouse/elan_i2c_smbus.c