Intel Precise Touch & Stylus

This is the userspace part of IPTS (Intel Precise Touch & Stylus) for Linux.

With IPTS the Intel Management Engine acts as an interface for a touch controller, returning raw capacitive touch data. This data is processed outside of the ME and then relayed into the HID / input subsystem of the OS.

This daemon relies on a kernel driver that can be found here: https://github.com/linux-surface/intel-precise-touch

The driver will establish and manage the connection to the IPTS hardware. It will also set up an API that can be used by userspace to read the touch data from IPTS.

The daemon will connect to the IPTS UAPI and start reading data. It will parse the data, and generate input events using uinput devices. The reason for doing this in userspace is that parsing the data requires floating points, which are not allowed in the kernel.

What is working?

• MS Surface Gen 4-6:
  • Stylus Input
  • Multitouch Finger Input
• MS Surface Gen 7:
  • Singletouch Finger Input
• HP Spectre 13 x2 (only non-surface device to use IPTS)
  • Entirely untested

What doesn't work?

• MS Surface Gen 4-6:
  • Multitouch pressure / contact area calculation
  • Finger tracking can glitch when pressing hard on the display
• MS Surface Gen 7:
  • Multitouch Input
  • Stylus Input
• HP Spectre 13 x2
  • Entirely untested

NOTE: The multitouch code has not been tested on all devices. It is very likely that it will still need adjustments to run correctly on some devices. If you have a device with IPTS and want to test it, feel free to open an issue or join ##linux-surface on Freenode IRC and get in touch.

Tested Devices:

• Surface Book 1
• Surface Book 2 (13" and 15")
• Surface Pro 4 (1B96:006A variant)
• Surface Pro 5
• Surface Pro 6

Building

You need to have a recent Go toolchain installed. It is developed with Go 1.14 but there should be no reason why older releases wouldn't work as well.

Reports and / or patches are welcome!

You also need to have the UAPI version of the IPTS kernel driver installed: https://github.com/linux-surface/intel-precise-touch

$ git clone https://github.com/linux-surface/iptsd
$ cd iptsd
$ go build
$ sudo ./iptsd

Installing

If you want to permanently install the daemon, we provide a systemd service configuration that you can use. If your distro does not use systemd, you will have to write your own definition, but it shouldn't be too hard.

Patches with support for other service managers are welcome!

You need to run the steps from "Building" first.

$ sudo cp iptsd /usr/bin/
$ sudo cp etc/systemd/iptsd.service /etc/systemd/system/
$ sudo cp etc/udev/50-ipts.rules /etc/udev/rules.d/
$ sudo cp -r config/ /usr/share/ipts
$ sudo systemctl enable --now iptsd

This assumes that you have the UAPI version of the kernel driver installed permanently, either by building your own kernel with it included, or by using DKMS.