Linux Kernel Project Update: Keyboard is working!

Project introduction here: http://charlieyou.me/linux0/

Max has figured out that if you disable the low power subsystem (LPSS) inside of the SPI driver (pxa2xx.c), then the applespi driver written by cb22 is able to do its job. In other words: the keyboard now works!

Well… mostly. Key rollover still does not work, so you can’t press two keys at the same time and have both be detected. Wakeup from keyboard also doesn’t work. The latter we’ll tackle along with sleep/hiberate issues. The former Max is trying to figure out now.

The immediate next step is to get the trackpad to work as well. Valid data is being read by the IRQ handler, so it should just be a matter of piping it to the correct place.

My focus is now on getting the internal speakers to work. Strangely enough, the headphone jack and internal mic work perfectly, it’s just the speakers that don’t output anything. There’s a bugzilla post for this that’s been a fairly helpful start: https://bugzilla.kernel.org/show_bug.cgi?id=110561. For an overview of the linux audio stack see this article: http://voices.canonical.com/david.henningsson/2011/12/08/audio-debugging-techniques/.

So far, I’ve played around with the patches mentioned in the bugzilla as well as hda jack retask to see if I could reroute to a different pin that is hopefully the speaker. No luck with that. Next I tried to just route the output to all unconnected pins, and that did get some sound from the speaker. Not the right sound and the kernel promptly panicked. But it’s something…

After this, the next things to tackle are:

  • Screen tearing
  • Bluetooth
  • Sleep/hibernate