June 2015 – technomasochism

Upgraded my laptop from an ancient HP 2760p so it’s time to write a new script to handle plug / unplug events from the docking station. Wait, what? Write a new script? Haven’t I done this before? Sure, I wrotea docking script for my Thinkpad x61s, but that was 6 years ago. No way that script still works … no wait it does!

Minor tweaks to sort out some differences between the udev events for the thinkpad / elitebook and changes to the xrandr command for my current monitor setup and it’s good to go!

The thinkpad had better integration with the kernel ‘dock’ driver so it generated different events for ‘dock’ and ‘undock’ events. For the EliteBook I had to trigger on the DRM kernel subsystem getting a ‘change’ event on ‘card0’. Not sure what that means but it’s consistent for plug / unplug. To determine whether the ‘change’ is docked or undocked I’m parsing xrandr output to see which monitor is present where. It’s not as nice but by parsing the output of xrandr it’s pretty simple. So the udev rule looks like this:

SUBSYSTEM=="drm", KERNEL=="card0", ACTION=="change", RUN+="/usr/local/bin/dock.sh"

And the script I’m now using for dock/undocking my EliteBook 820 G1 on Debian 8.0 is here.

Thanks for doing me a solid past me. Well done.

I spent a few hours last night customizing the awesome window manager (wm) on my new laptop install. I’ve been using awesome for a while now (years) but I haven’t done much by way of customizing my setup. The default config from Debian, with a few small tweeks to default tags and layouts, has been sufficient. But having a battery gauge on my laptop is pretty important so I carved out a few minutes to set this up.

As always I’m not the first person to have this problem. Luckily those that came before me put their work up on github so all I had to do was clone awesome-batteryinfo, copy battery.lua into my ~/.config/awesome directory and integrate the battery widget into my rc.lua.

Integrating this widget is pretty painless. There are four steps: First you have lua pull in battery.lua:

require("battery")

Second you instantiate the widget:

mybatterywidget = widget({type = "textbox", name = "batterywidget", align = "right" })

Third you place the widget in a wibox. Debian has a wibox positioned across the top of each screen. I took the batterywidget created above and added it to the wibox widget list along side the layoutbox, textclock etc. My final mywibox.widgets looks like this:

mywibox[s].widgets = {
    {
        mylauncher,
        mytaglist[s],
        mypromptbox[s],
        layout = awful.widget.layout.horizontal.leftright
    },
    mylayoutbox[s],
    mytextclock,
    batterywidget,
    s == 1 and mysystray or nil,
    mytasklist[s],
    layout = awful.widget.layout.horizontal.rightleft
}

Finally I set up a timed event to update the widget every 20 seconds. I also seeded the widget text to show the battery data at the time the widget is created. This means that the widget will come up with meaningful data before the first even fires (20 seconds after init):

-- seed the battery widget: don't wait for first timer
mybatterywidget.text = batteryInfo("BAT0")
-- timer to update battery widget
mybatterywidget_timer = timer({timeout = 20})
mybatterywidget_timer:add_signal("timeout", function()
    mybatterywidget.text = batteryInfo("BAT0")
end)
mybatterywidget_timer:start()

That’s all there is to it. Thanks to koenwtje for the great widget. I should probably collect my awesome configs into a git repo so I don’t have to go back and rediscover how to do this every time I build a new system …

Month: June 2015

HP Elitebook 820 G1 laptop dock script

awesome battery widget