Build newer Qt version (Qt 5.12) together with Linux Toradex 2.7b6


We are using Angstrom Toradex Linux v 2.7b6, and due to some driver compatibilities we need to be exactly on 2.7b6.

However we need to build newer Qt version like Qt 5.12 alongside with Angstrom Toradex Linux v 2.7b6 and populate SDK with Qt 5.12.

Any try to update git tag of the qt and update meta recipes, but unfortunately we were enable co compile anything.

How can we change the Qt version included into Angstrom Toradex Linux v 2.7b6 populated SDK to be different than default included in the repository, for example Qt 5.12?


Unfortunately, Qt having major dependencies to many another thing, mixing and matching Qt (and many other a thing for that matter) version is not easily possible. I’m wondering what exact driver compatibilities you are talking about.

It is all about SPI driver timing in burst DMA transfer, there are pauses at about 160us between every burst of the SPI.

We made our custom patch to the SPI driver into 2.7b6 version by modifying “water level” and some other staff in order to use the DMA interrupt and speed up the timings of the SPI.

In general in the Linux Kernel the SPI silicon errata of i.MX6 is fixed the easy way by lowering the watermark of the DMA, but we definitely need to avoid these 160us delays between transfers because they ruin our ADC total sampling rate.

Unfortunately our patch to the SPI driver does not affect the driver version in Toradex Linux 2.8b4 where it is different. In the 2.8b4 the SPI driver burst throughput is even worse and because of that we need to stuck to 2.7b6.

Anyway, even if we decide to fix the SPI driver and somehow migrate to 2.8b4 the Qt version is 5.9 and again we can’t compile Qt 5.12 alongside SDK, so we don’t gain anything.


But why exactly do you think you really need Qt 5.12?

I want to give a try to Qt 5.12 because we experience some “Segmentation Fault” crash, cause by “QNetworkReply” in “QNetworkAccessManager” if something is wrong with WiFi connection. That crash happens from time to time and seems to be kind of random, but most likely when WiFi connect->disconnect->reconnect quickly.

When we use different library for GET Rest requests, like for example BOOST library instead of Qt Network Request it does not crash, sometimes simply time out, but that is normal, compared to “Segmentation Fault” when we use Qt library.

We want to figure out if there is some Qt bug into that library that may be fixed in 5.12 version. Kind of desperate last try of using QNetworkAccessManager, before switch to BOOST library instead for that part of the code.


You may want to run your stuff in a debugger to figure out where exactly it crashes, then look at recent changes/fixes whether or not that may already be addressed and just backport resp. fix.