ELANSMBus

This repo is no longer maintained. Refer to https://github.com/leo-labs/VoodooSMBus for an improved version.

The objective of this project is to provide support to the ELAN Touchpads which use SMBUS to report the touch information. It has been created to work on the Thinkpad T480s.

"New ICs are using a different scheme for the alternate bus parameter. Given that they are new and are only using either PS2 only or PS2 + SMBus Host Notify, we force those new ICs to use the SMBus solution for enhanced reporting. This allows the touchpad found on the Lenovo T480s to report 5 fingers every 8 ms, instead of having a limit of 2 every 8 ms." https://patchwork.kernel.org/patch/10324629/

Requirements

• Obvious, but make sure that you have an ELAN touchpad connected via PS2 & SMBUS. (you can confirm this by using lspci in Linux)
• Basic knowledge about hotpatching, kext installation, plist modification. As no support regarding this topics will be provided.
• Rehabman VoodooPS2Controller.kext for the keyboard to work.
• Latest version of ElanSMBus.kext provided here.
• SMBUS hotpatch provided here SSDT-SMBUS.dsl and config.plist patches similar to CoolStar ones SMBUS patches.
• Disable the trackpoint in Bios settings. (Trackpoint support not implemented yet)

Installation

• The VoodooPS2Mouse plugin from VoodooPS2Controller.kext must be disabled or deleted (less elegant), so our touchpad do not use the PS2 interface to report the information and the initialization is done via SMBUS.
• Add the SMBUS patches to the config.plist file (in the KextsToPatch section) to avoid the use of AppleSMBusPCI and AppleSMBusController kexts or remove them (again less elegant).
• Add the SMBUS hotpatch SMBUS.dsl, it just creates a device representing the touchpad so the kext can be attached to it.
• Remove AppleIntelLpssiI2C.kextand AppleIntelLpssiI2CController.kext (If there is no "replacing" kext they get loaded and the driver does not work).
• Install the ElanSMBus.kext in /L/E
• Update kext cache sudo kextcache -i /
• Reboot and done.
• Do not touch the touchpad while booting.

To Do

• Power management has not been implemented so the touchpad does not work after Sleep.
• The trackpoint information could be also retrieved, so I think it would be possible to use the Thinkpad trackpoint as well.
• Find how to avoid the deletion of AppleIntelLpssiI2C.kext and AppleIntelLpssiI2CController.kext (more elegant).
• Test some changes to fix the no touch while booting. (Some delays added in the initialization could/should be removed)

License

Follow the GPL3.0 license as per LICENSE.txt

Acknowledgements

Thanks to:

• @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
• @benjamin.tissoires for the Linux kernel drivers.
• @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

Improvements and collaboration

Please feel free to propose and/or share anything you think that might be useful.