Building v3 for ARM64... and the failure within

[hydrochloriic]

Hello!

For reasons I can barely explain (low power telemetry display for racing), I thought it would be a good idea to try to build v3.0.6 from the source on a Raspberry Pi (5, but started with a 3B+) inside Ubuntu 25.04. Originally I was attempting in Raspbian but Debian doesn't yet have some of the Qt packages in Debian 12, so eventually required a switch to Ubuntu. After that, this was a huge hassle in getting the proper Qt libraries, plugins, etc. Once those hurdles were cleared, I started having issues with includes. Finally moving files around and correcting a line that was wrong in the CSV output... The build failed. This time it was due to an unsupported sse2 instruction. I gambled, disabled the sse2 flag in cmakelists, and sent it.

Shockingly, it built. Unsurprisingly however, it doesn't run. Seems that the QQmlApplicationEngine is failing to create the main window, based on the gdb output. I'm already quite out of my depth (enough familiarity with C on embedded hardware I could try things but this is beyond my norm!) and at this point the original purpose is beyond when I was hoping to have it ready for. Of course I'm stubborn and still want it to work... 😄

Here is the output from gdb, in case anyone has some ideas, but I'm running out of steam now.

[New Thread 0xffffce129b60 (LWP 38426)]
QQmlApplicationEngine failed to load component
qrc:/serial-studio.com/gui/qml/main.qml:62:3: Type MainWindow.MainWindow unavailable
qrc:/serial-studio.com/gui/qml/MainWindow/MainWindow.qml:314:9: Type Panes.Setup unavailable
qrc:/serial-studio.com/gui/qml/MainWindow/Panes/Setup.qml:301:9: Type SetupPanes.Hardware unavailable
qrc:/serial-studio.com/gui/qml/MainWindow/Panes/SetupPanes/Hardware.qml:104:9: Type Drivers.Modbus unavailable
qrc:/serial-studio.com/gui/Modbus.qml: No such file or directory
[CRIT] Critical QML error
[Thread 0xffffcf7eeb60 (LWP 38425) exited]
[Thread 0xffffe4e96b60 (LWP 38422) exited]
[Thread 0xffffcfffeb60 (LWP 38423) exited]
[FATL] QThread: Destroyed while thread is still running

Thread 1 "serial-studio" received signal SIGABRT, Aborted.
Download failed: Invalid argument.  Continuing without source file ./nptl/./nptl/pthread_kill.c.
__pthread_kill_implementation (threadid=281474830017824, signo=signo@entry=6, no_tid=no_tid@entry=0)
    at ./nptl/pthread_kill.c:44
warning: 44	./nptl/pthread_kill.c: No such file or directory

[alex-spataru]

Hi,

I think the issue’s on my end while building the app with Qt open source.

Also, the Qt version in the Raspberry PI repos is probably too old for Serial Studio (it needs at least 6.5, and I think it's still stuck on 6.2)....don't know about Ubuntu. And that's why I usually ship AppImages for Linux users 😂

You’ll likely have better luck installing Qt for ARM Linux from here, make sure to grab the ARM64 installer.

I’ll update you as soon as I’ve tested the open source build and pushed the changes. I’m also planning to add an option to force software rendering for the QML user interface, since the Raspberry Pi probably doesn’t have proper GPU support.

Thanks for the report, and good luck on your project. Would love to see some photos when we get it to work!

[hydrochloriic]

So interestingly, I started with the official Qt installer for ARM. With the entirety of Qt 6.8.3 and Qt Creator installed, it was missing a lot of packages. That was true on both Raspbian and Ubuntu. Directly installing the packages was still required.

You're right about the RPi repos though, they are fairly old (though Debian 12 is also out of date so that's not surprising). Part of the reason I switched to a 5 was so I could use Ubuntu 25.04, which the old 3B+ didn't even have enough RAM for- Ubuntu has all the Qt packages available.

Thanks for looking, and I'll keep an eye out for the new open source build! Luckily I've already confirmed the setup otherwise works on a windows laptop, but the solar power station can't usually keep that running for the whole day of racing.

[alex-spataru]

Just pushed a commit that should fix the runtime issue. Turns out I was a bit of an idiot and accidentally loaded a QML component that’s only available in the commercial Qt build. Should be sorted now, let me know how it runs on your end.

By the way, if we get this working smoothly, it might be worth putting together a wiki entry or even an example project with step-by-step instructions on building and running Serial Studio on the Raspberry Pi. Could save a ton of people from this headache down the line. Some years ago I wrote a script to do that, but at that time Serial Studio was based on Qt 5.

[alex-spataru]

By the way, you might want to keep an eye on this issue. @JamesBrosy is adding Serial Studio to Flathub, which could make installing Serial Studio on arm64 Linux installs much easier in the future.

[calyle]

By the way, my build script is support to v3.0.6. The continuous version adds some other features, and I may do some adjustment later. And the flatpak version may come later, because tag v3.0.6 hasn't what I add in. Look forward to a new release as soon as possible.

[hydrochloriic]

I'll take a look at the flathub setup, just a quick update to say that the update did in fact build and run! Unfortunately at least plots are non-operational and about 75% of the time it crashes on disconnect. Haven't looked any further into it as the racing begins tomorrow.

After the weekend is over I'll take another look at everything that I had to do to get it to build, probably start over and take careful notes, which I wasn't doing in my rush this time.

[alex-spataru]

By the way, my build script is support to v3.0.6. The continuous version adds some other features, and I may do some adjustment later. And the flatpak version may come later, because tag v3.0.6 hasn't what I add in. Look forward to a new release as soon as possible.

Thank you very much for the help, I'll let you know when I draft a new release. Currently I'm working on some redesigns in the dashboard UI due to the requirements of a client...basically Serial Studio will get much better navigation and organization features for complex dashboards, plus option to run full screen without toolbar for HMI operator interfaces.

I believe I'll finish with everything (including translations) by the end of May.

[alex-spataru]

I'll take a look at the flathub setup, just a quick update to say that the update did in fact build and run! Unfortunately at least plots are non-operational and about 75% of the time it crashes on disconnect. Haven't looked any further into it as the racing begins tomorrow. After the weekend is over I'll take another look at everything that I had to do to get it to build, probably start over and take careful notes, which I wasn't doing in my rush this time.

Nice, great to hear it built and ran! That’s a win in itself.

Yeah, I’m not too surprised the plots aren’t working...Serial Studio might ask too much from the Pi 3B, especially since the UI relies heavily on OpenGL.

Crashing on disconnect could be related to GPU context loss or just the system getting overwhelmed. A Pi 4 or 5 would probably handle it a lot better.

I’ll look into adding aarch64/arm64 Linux CI builds soon to make things smoother for setups like this. I see lots of interesting applications of Serial Studio for Raspberry Pi.

Also, how’d the race go?

[alex-spataru]

Hi @hydrochloriic, just to let you know that arm64 builds of Serial Studio are now available as AppImages in the continuous builds.

Not sure how well it’ll perform on a Raspberry Pi 3, but at least you can skip the compile step. I’ll also be adding an optional toggle in the preferences to force software rendering for systems without a GPU.

Here’s a screenshot of Serial Studio running inside an Ubuntu 24.04 arm64 VM:

Please let me know if it works on your end!

[alex-spataru]

Screenshot with plots. Performance in the Ubuntu arm64 VM is looking pretty good. Also added SIMDE-based optimizations that enable NEON instructions for handling plotting data. A few weeks ago, SSE2 was being emulated instead of using native arm64 aliases.