Why Qt platform plugin “xcb” cannot be loaded even though it was found?

Pablo J. Rogina

@rrd0 from your error log please see entries like this

qt.qpa.xcb: could not connect to display

that coupled with the way you said you're starting your app

when I try to run the same app from a remote debug session

seems to me that you're not using a SSH session with X Forwarding... don't forget the -X parameter along with proper hosts authorization

ssh -X user@hostname

rrd0

@Pablo-J.-Rogina

I'm not using X forwarding. The app is displayed on the target. Just text (stdout and stderr, I guess) is displayed on my dev machine.

SGaist

You still have to configure things properly. You are starting your application remotely, so you have to configure your session so that your application tries to connect to the local X server.

rrd0

@SGaist

QtCreator has a tab to set Host, SHH port, username, key file, etc. But there's no box where I could enter that -X option.

Could you give me some pointers?

rrd0

This post is deleted!

SGaist

I may be wrong but I don't think you currently can.

Out of curiosity, what is the reason for having a full X server running on your embedded target ?

hskoglund

Hi, I also run Qt apps on my Raspberry Pi, and when I had problems using the -platform xcb to connect to them, I instead use -platform vnc works fine.
(On my PC I use vncviewer.exe to connect)

rrd0

@SGaist

I'm using X cause I tried (a lot) to run my apps on EGLFS with no success. I followed the RaspberryPi2EGLFS guide, from qt wiki, to build Qt for RPi, but never managed to make it work.

Do you know some other guide that could help me build Qt (EGLFS) for RPi?

P.S. Someone updated the RaspberryPi2EGLFS guide, so I'll give it a last try.

rrd0

@hskoglund

I'll try that. Thanks!

SGaist

Any chance you are having trouble using a Raspbian Stretch root filesystem ?

rrd0

@SGaist

What kind of trouble?

SGaist

The EGLFS issue.

rrd0

@SGaist

Raspbian Stretch is the distribution used in RaspberryPi2EGLFS guide, and I followed each one of the steps described in that guide. So, I don't think there's something wrong with my root filesystem.