Raspberry Pi Qt project

[Peter Vincent]

I followed the instructions for building and running a Qt project on a Raspberry Pi from Windows VS 2017 (not with a cross compiler). It works brilliantly. However, when I run I see an error when the program starts but which doesn’t seem to cause any problems. First on VS2017 with X-Window running:

failed to get the current screen resources
QXcbConnection: XCB error: 170 (Unknown), sequence: 170, resource id: 90, major code: 146 (Unknown), minor code: 20

If I run directly on the RPi then I see a different error which might or might not be related.

libEGL warning: DRI2: failed to authenticate

** (Turing-Bombe:1979): WARNING **: Error retrieving accessibility bus address: org.freedesktop.DBus.Error.ServiceUnknown: The name org.a11y.Bus was not provided by any .service files
Gtk-Message: GtkDialog mapped without a transient parent. This is discouraged.

However, in both cases the program itself runs fine. Should I just ignore or is there some fine tuning to the setup needed?

[support]

Hi,

This looks like a configuration problem on your Raspberry Pi. Please try using a clean SD card image and installing Qt on top of it, or follow these instructions on repairing libEGL permissions.

[Peter Vincent]

I tried a complete reinstall of my RPi this morning using the most recent version of Raspbian “RASPBIAN STRETCH WITH DESKTOP, Image with desktop based on Debian Stretch, Version:November 2017, Release date:2017-11-29, Kernel version:4.9“. I then built the sample Qt5 project on Visual Studio 2017 to get everything back in place, including installing the Qt5 files on the RPi, which works fine but gives the same error messages.

I will try the alternative suggestion now.

[Peter Vincent]

I tried to follow the attached instructions and afterwards nothing worked! So rebuilt again but took note that there was a problem with some Qt bits in the Raspbian distribution, so found and purged these first then created a new Qt project on Visual Studio to install Qt5. Now everything appears to work OK.

[support]

Hi,

Good to know it works. If you encounter further problems, do not hesitate to post another thread.

[Author]

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