Unformed notes from getting my Pinebook Pro to work well :)

1. The machine comes with Manjaro on it, which works fine, but it has no
   full-disk encryption so I'm going to need to reimage it. To do that, I need
   a microsd card unless I want to risk overwriting the eMMC - but if I do that
   and screw up, I have no backup plan, so :grimace:

2. The brightness-up/brightness-down keys *appear* (according to xev(1)) to
   deliver XF86MonBrightness{Up,Down} but actually they don't - instead, they
   generate acpid events, which you can hook up via /etc/acpi/events. I ended up
   making two files like:

     event=video/brightnessup
     action=/usr/local/bin/backlight +10

   and those basically did the job.

3. You can control the backlight via sysfs: /sys/class/backlight/edp-backlight

4. The battery is in sysfs at /sys/class/power_supply/cw2015-battery, but that
   appears to have less info than upower(1) does - in particular, how does one
   figure out the remaining charge of the battery? You could work it out from
   time_to_empty_now (minutes), current_now (microamps?), and charge_full
   (microamp-hours?). However, you can snag these things out of uevent in that
   directory, at the price of a bit of parsing.

5. Point 2 was wrong - my actual problem was what I had two separate i3 configs,
   one at ~/.i3/config and one at ~/.config/i3/config, and I was editing the
   wrong one. Oops! Instead I could do:

     bindsym XF86MonBrightnessUp exec backlight +10
     bindsym XF86MonBrightnessDown exec backlight -10

  using the backlight tool from ~elly/onek, although it's pretty easy to rewrite
  it for whatever other system's backlight.

6. Getting the ssh pubkey off the system turned out to be a pain in the butt,
   and I ended up doing:

     remote$ nc -l -p $PORT > ssh-key
     local$ nc remote $PORT < .ssh/id_ed25519.pub

   and then checking the sha256sum at both ends. It's annoying how much of a
   problem this still is in the year 2021.

7. The `vi` on this system is sad and I keep running it by accident. :(