Enable native/true multitouch gestures

[kprinssu]

I am creating this PR to show that it is possible to enable native multitouch on PS/2 trackpads. My laptop comes with a Synaptics PS/2 trackpad and this is a more of a PoC than anything else.

A lot of the work here was hacked together using VoodooI2C's native multi touch engine (though it's from an older commit) and the synaptics driver from the Linux kernel.

It currently supports 3+ fingers gestures so it should fully support most of Macbooks gesture. However, my laptop only seems to support a max of three fingers and gestures sometimes feel off.

I also had emulate the third finger since the trackpad doesn't report back on more than 2 fingers.

Based on Rehabman's upstream branch, but should be relatively easy to backport the changes. Feel free to edit and merge the code at your leisure.

[syscl]

Hi thank you so much! I want to merge it but it shows merge conflicts 😟

[syscl]

Hi thank you so much! I want to merge it but it shows merge conflicts 😟

[kprinssu]

I’ll rebase and apply some additional clean up so there aren’t conflicts with master.

[syscl]

Awesome! I will test it today then merge it!

[kprinssu]

Few things to note:

• physical clicks do not work properly (working on this right now) (f4e680d should make this work)
• 3+ fingers pinch gestures do not work (not sure how to spoof this data) due to the limitation of the touchpad not sending more than 2 finger data
• 4 fingers do not seem on my trackpad device (not sure why, since 4 fingers are recognised by libinput on Linux)
• naming collisions with VoodooI2C classes (need to rename the Multitouch Support classes from VoodooI2C* to VoodooPS2*?)
• only Synaptic based PS2 trackpad works (I do not have other PS2 based devices to test this on)

[syscl]

Nice! As for the renaming, sounds good to me:)

[syscl]

Hi @kprinssu , I've tested it on my Precision M3800, and this driver is really good!

In short, the two finger gestures (left/right swipe forward/back), three finger taps, dragging, work like a charm. I have a MacBookPro 13, 2018 with Touch Bar, and I feel these touchpad is quite usable now!

Thank you so much!

[syscl]

@kprinssu could you please tell me why this implementation will make the touchpad much precise and smoother, I'm really looking forward to the details. Thank you in advance!

[kprinssu]

Good to hear! I still find that it still abit jerky and will require more tuning.

There are more changes from VoodooI2C that I want to backport but this PR should be good to go, unless you want me to clean up code.

[syscl]

Thank you, I've already submitted a collaboration request for you 😃