Turning a Dell Wyse 3040 into an HTPC (Part 5)

Output switching

We�ve been putting together an HTPC using a Dell Wyse 3040 thin client PC. We’re using Arch Linux as an OS, and installed media applications Kodi and Chromium (to give us Netflix). We also installed Openbox to provide a window manager, and set up control of applications via remote using FLIRC. Now I’d like extend my viewing options with an extra display.

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Interested in more info on the Wyse 3040? ParkyTowers has a treasure trove of info on the hardware, disassembly, firmware, installing TinyCore Linux, and some further reading. Enjoy!

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Wyse3040 Video Outputs

The Wyse 3040 is pretty small as computers go, about the size of a hand. It’s bigger than a Roku stick or a single-board computer like a Raspberry Pi or an Odroid, but still small. Thankfully on the back along with power, network and USB it packs in two DisplayPort outputs.

I’ve been using one output with a cheap active DisplayPort-HDMI adapter, which goes to the old Samsung 50″ plasma TV via an Onkyo audio receiver (HDMI in ? audio out via speakers + video out via HDMI). The problem is that plasma TVs are incredibly power-hungry.

I measured it, and got between ~250 and 325 W! That’s… not fun given energy bills have shot up (ca. 47p per kWh at time of writing). I don’t want to buy a whole new TV when i got this one for free when someone was disposing of it, but nor do I particularly want to fall asleep with the thing on all night! Extra-unfortunately it doesn’t standby when losing signal (a big deficit for a plasma TV- keeping that “No Signal” on the screen must be horrid for burn-in), nor does it have a sleep timer/mode.

Enter this tiny 15″ monitor! Drawing a respectable 9W, if I did fall asleep with this on it would still consume less power than an hour of watching the plasma TV. Even better, it does sleep when it loses signal, so I can configure Kodi to disable the display output when idle and the monitor will drop to standby for even more power savings. I tested an old 15″ Dell monitor too, and it also draws 9W. I knew keeping those around for years would pay off!

Kodi Doesn’t Want to Switch Display

Having hooked the 15″ monitor via an active DisplayPort-VGA adapter (I can’t remember what I bought it for, but it came in handy!) I can see that Kodi runs just fine on a small resolution�.

(�: Side note: I remember when 1024×768 was a big step up from 800×600, around the Jedi Knight era? Not quite the dizzying heights of 1280×1024 in the BF2 days, but more than 1000 horizontal pixels- what a step up!)

Unfortunately, using Kodi’s own menu didn’t actually change the display; just made it display the 1280×720 TV-sized output on the monitor itself. D’oh. I was able to get this working via xrandr:

# Monitor
xrandr --output DP-1 --primary --mode 1024x768 --pos 0x0 --rotate normal --output HDMI-1 --off --output DP-2 --off --output HDMI-2 --off --output DP-3 --off --output HDMI-3 --off
# TV
xrandr --output DP-1 --off --output HDMI-1 --off --output DP-2 --off --output HDMI-2 --off --output DP-3 --off --output HDMI-3 --primary --mode 1280x720 --pos 0x0 --rotate normal

From there I created one liner executable scripts with these incantations, and hey presto! I can change resolution from the command line (remembering to prefix with DISPLAY=:0), which is nice, if a little inconvenient.

Kodi Loses Text and Updating Arch

Unfortunately, something in here caused Kodi to forget how to display text after playing a video or going into screen-dim mode.

It turns out this was a known issue, which was subsequently fixed in a merged PR. This being an HTPC — motto: “get it working then don’t dare touch it” — it hadn’t been updated in quite a while (er, 2020) and was still running Kodi 18.8.

Arch needed to be updated, and good practice is to:

1. review the homepage for breaking changes
2. update archlinux-keyring (avoids eg “error: libffi: signature from "Levente Polyak (anthraxx) levente@leventepolyak.net" is unknown trust“)
3. full system update

Unfortunately I hit a couple of stumbling blocks:

pacman claims that “archlinux-keyring-20210110-1 is up to date”

For some reason, the mirror I had a the top of my mirrorlist (/etc/pacman.d/mirrorlist), UK Fast, was distressingly out-of-date. Using Mirrorservice sorted that and got archlinux-keyring 20220424-1 installed nicely.

pacman: error: Partition / too full: 237835 blocks needed, 90267 blocks free (ie Wyse3040 is too small to update)

Oh, um.

df -h /
Filesystem           Size  Used Avail Use% Mounted on
/dev/mapper/vg-root  6.7G  6.0G  353M  95% /

That’s a problem. The Wyse3040 I have has a comparatively tiny amount of storage. I went through the filesystem with ncdu and removed a few bits of low-hanging fruit, but it was clear deleting a few things here and there wasn’t going to butter the parsnips.

Instead I remote-mounted the package cache (/var/cache/pacman/pkg) on my desktop PC. If that sounds horribly janky to you… you’d be right. But it worked!

Side note: no chance it would have succeeded on the Wyse-

# on PC
$ du -sh /tmp/wyse3040/
1.9G    /tmp/wyse3040/
# <.<   >.>

Switching Outputs Nicely

Now that we have a script that can switch between the monitor and a TV, it’s time to make it work more conveniently than ssh-ing in from a phone. Yup, it’s FLIRC time again!

[ flirc image ]

My preference is to map this on to the audio receiver’s remote. I think this works better than the TV remote for a couple of reasons:

• there’s quite a lot mapped on there, and I don’t want to accidentally hit the “change output” button[s] during normal video interaction- “I meant to hit pause, or mute, where did the picture go?”
• I already have audio balance (all L / all R / centre) mapped on the audio receiver remote, and this feels like a video analogue- instead of shifting the direction the audio si coming from, I’m shifting the direction the video is coming from

First, set up (add) the keyboard shortcuts in (to) ~/.config/openbox/rc.xml:

<?xml version="1.0" encoding="UTF-8"?>
<openbox_config xmlns="http://openbox.org/3.4/rc" xmlns:xi="http://www.w3.org/2001/XInclude">
        <keyboard>
                <!-- Run Kodi or Netflix -->
                <keybind key="W-k">
                        <action name="Execute">
                                <command>/home/robert/code/media_switcher/media_switcher.sh "kodi"</command>
                        </action>
                </keybind>
                <keybind key="W-n">
                        <action name="Execute">
                                <command>/home/robert/code/media_switcher/media_switcher.sh "netflix"</command>
                        </action>
                </keybind>
                <keybind key="W-c">
                        <action name="Execute">
                                <command>killall chromium && chromium &</command>
                        </action>
                </keybind>
                <!-- Change audio balance L | C | R -->
                <keybind key="W-4">
                        <action name="Execute">
                                <command>/home/robert/scripts/balance.sh left</command>
                        </action>
                </keybind>
                <keybind key="W-5">
                        <action name="Execute">
                                <command>/home/robert/scripts/balance.sh centre</command>
                        </action>
                </keybind>
                <keybind key="W-6">
                        <action name="Execute">
                                <command>/home/robert/scripts/balance.sh right</command>
                        </action>
                </keybind>
                <!-- Switch between TV and monitor -->
                <keybind key="W-7">
                        <action name="Execute">
                                <command>/home/robert/.screenlayout/mon.sh</command>
                        </action>
                </keybind>
                <keybind key="W-9">
                        <action name="Execute">
                                <command>/home/robert/.screenlayout/tv.sh</command>
                        </action>
                </keybind>
        </keyboard>
</openbox_config>

The latter two entries map ? Win + 7 and ? Win + 9 to the monitor and TV xrandr scripts respectively.

Then in FLIRC:

Done!