Hardware Shenanigans

(originally titled “On Dead Trees”)

There’s features that you know are really important to some of our users but you frankly don’t really care for them much yourself. Printing is one such example. Recently, I actually had to print lots of paperwork, so I had a reason to fix some of my more pressing issues with our Print Manager.

The biggest regression from the Plasma 4 days, when we moved from individual System Tray popups to a unified square view, was that Print Manager had to give up its two pane layout that showed the print queue directly in the popup. In order to view and cancel print jobs, you now had to select the printer and open its print queue window, and close it again after you’re done.

Unfortunately, with printer management, there’s really two opposing use cases: a home computer with maybe a couple of printers, and the office use case of hundreds of remote printers across several buildings. Picking one side usually leaves the other one worse off. However, I did not want to spent too much time on this, so in order to fix my workflow, I simply added the list of print jobs in the expanded view. I then added a busy indicator to a printer when it’s printing to make it easier to find in the list.

CUPS error messages have never been very nice and with all that “driver-less” stuff the user experience seems to have become worse, spitting technical gibberish like “cfFilterChain: Ghost script (PID 123456)” at the user. While printing probably works better now, the overall feature set has definitely regressed for me. In order to accommodate status messages better, Print Manager now shows up to three lines of text, which is particularly important in case of a printer or network error.

Another nice little touch from Plasma 4 was a dedicated laser printer icon. At home I have a black and white laser printer for printing documents and a color inkjet for printing pictures. It’s really nice being able to tell them apart at a glance. Therefore, I added a laser printer icon to Breeze as well. However, when I investigated how it worked, I found it just assumes every black and white printer to be a laser printer. Fair enough. You can ask CUPS for the “marker type”, e.g. toner or ink, and I hoped that I could use it to determine the printer type more accurately. Alas, since updating to the Ubuntu 24.04 base, none of my printers show ink levels anymore, not even after installing the official vendor drivers. Either way, ink status has been hit or miss for me under Linux for as long as I can remember, sometimes randomly working when talking to the printer over the network but not on the computer it was plugged into via USB and so on.

Next, while tinkering with printer settings, I noticed the nice little search box we have in our settings dialogs nowadays. Trying to find a certain option, I was surprised it didn’t highlight it, even though I clearly typed the exact name on the label. You see, controls in Qt can have “mnemonics” or “accelerators”, this is the underlined letter you typically see on a button that tells you what Alt+key to use to trigger it. The letter is prefixed with an ampersand (&) in the string, so “Pap&er size” shows as “Paper size” and will trigger on pressing Alt+E. KDE applications automatically assign a free accelerators to most widgets unless explicitly provided through the ampersand notation. The settings search did not account for this and subsequently failed to find it.

Leaving the subject of printers for now, I made a few minor improvements regarding batteries. One of my earliest contributions to Plasma’s power management system over ten years ago was a notification when a peripheral device, such as mouse or keyboard, runs low on battery. While the notification showed a dedicated icon for headsets (i.e. headphones with a microphone) it did not provide one for regular headphones, and neither did battery monitor, but it was an easy fix.

Additionally, when switching output devices, a brief on screen display is shown. In case of Bluetooth devices, battery status is included alongside the device name, to quickly see when the headphones you just connected are almost out of juice. When I switched to PipeWire this stopped working, no battery percentage was shown. I didn’t fully understand how it works but with PulseAudio it probably has exclusive access to the Bluetooth device and is the one that has to read the battery information and provide it to others as audio device property. With PipeWire, I guess things are different, and I just get to read battery information over the regular BlueZ battery interface, so that’s what Plasma will consult before showing the device popup.

Finally, the Energy Information page now displays the number of charge cycles your laptop battery has experienced so far in addition to the capacity estimation (“battery health”). The ability to query this information was added to Solid, KDE’s Hardware Abstraction Framework, and is supported by all of its backends. My trusty ThinkPad has over 700 charge cycles now and still reports 77% capacity left. I was still quite happy with its battery life during this year’s Akademy – admittedly I didn’t compile much during talks and had the screen brightness very low.

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