Wednesday, November 2, 2016

libinput beginner project - disabling touchpads on lid close

Update: Dec 08 2016: someone's working on this project. Sorry about the late update, but feel free to pick other projects you want to work on.

Interested in hacking on some low-level stuff and implementing a feature that's useful to a lot of laptop owners out there? We have a feature on libinput's todo list but I'm just constantly losing my fight against the ever-growing todo list. So if you already know C and you're interested in playing around with some low-level bits of software this may be the project for you.

Specifically: within libinput, we want to disable certain devices based on a lid state. In the first instance this means that when the lid switch is toggled to closed, the touchpad and trackpoint get silently disabled to not send events anymore. [1] Since it's based on a switch state, this also means that we'll now have to listen to switch events and expose those devices to libinput users.

The things required to get all this working are:

  • Designing a switch interface plus the boilerplate code required (I've done most of this bit already)
  • Extending the current evdev backend to handle devices with EV_SW and exposing their events
  • Hooking up the switch devices to internal touchpads/trackpoints to disable them ad-hoc
  • Handle those devices where lid switch is broken in the hardware (more details on this when we get to this point)

You get to dabble with libinput and a bit of udev and the kernel. Possibly Xorg stuff, but that's unlikely at this point. This project is well suited for someone with a few spare weekends ahead. It's great for someone who hasn't worked with libinput before, but it's not a project to learn C, you better know that ahead of time. I'd provide the mentoring of course (I'm in UTC+10, so expect IRC/email). If you're interested let me know. Riches and fame may happen but are not guaranteed.

[1] A number of laptops have a hw issue where either device may send random events when the lid is closed


Søren Hauberg said...

Perhaps related: some laptops (E.g. Lenovo Yoga laptops) allow the lid to be flipped behind the screen, turning the laptop into a tablet. Here you also want to disable the touchpad (doesn't currently happen). Perhaps it is the same problem just with a different event?

Sebastian said...
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