Qt 5.12.2 Raspberry Pi X11

sierdzio

@sierdzio said in Qt 5.12.2 Raspberry Pi X11:

sudo apt-get install "^libxcb.*"

This line should have installed libxcb. Weird! Last time I tried, I think I was compiling Qt 5.10.1. Try with that version perhaps? More importantly, though - make sure you update your sysroot after installing all these new dependencies.

Lashc

@sierdzio @jsulm Compiling Qt 5.10.1 instead did the trick! I don't think there's anything I'll miss from Qt 5.12. Thank you all so much!

SGaist

Hi,

Since Qt 5.12.1, xkbcommon is not provided anymore as all older platforms supported now provides that dependency.

Lashc

@SGaist I checked to see if I have any xkbcommon packages installed on my Raspberry Pi, and I discovered the following ones:

libxkbcommon-dev, libxkbcommon-x11-0, libxkbcommon-x11-dev, and libxkbcommon0

I tried to compile Qt 5.12.2 again, but I still received errors about xkbcommon and xcb.

SGaist

Which version are they ?

Nikhilesh N

This topic has garnered my interest, and I'll follow it from now. Getting to know very interesting revelations by the way, Samuel.

Lashc

@SGaist Here's a list of the packages and their respective versions:
libxkbcommon-dev: 0.7.1-2~deb9u1
libxkbcommon-x11-0: 0.7.1-2~deb9u1
libxkbcommon-x11-dev: 0.7.1-2~deb9u1
libxkbcommon0: 0.7.1-2~deb9u1

hlmjr

This is due to changes in Qt's configure system in 5.12+. Namely, commits like this one: https://github.com/qt/qtbase/commit/e80bf655e922e9864f8843b5e7bbb47019a6d95a

Anywhere there once was "include": "suchandsuch" inside a test that was changed to "headers": "suchandsuch" outside the test fails now when cross-compiling for Raspbian.

I'm in the process of trying to find and revert them all but have gotten stuck on the somewhat more complicated Xlib detection:

"xlib": {
	"label": "XLib",
	"test": {
		"main": [
			"Display *d = XOpenDisplay(NULL);",
			"XCloseDisplay(d);"
		]
	},
	"headers": "X11/Xlib.h",
	"sources": [
		{ "type": "makeSpec", "spec": "X11" }
	]
},

It's that { "type": "makeSpec", "spec": "X11" } line that is failing. I'm not yet sure how to modify that one. Once I figure this out I'll open a bug and see if we can boil it down to a root cause. I'm sure the way I'm adjusting the configure.json isn't quite correct.

/ranton How changes that can break this on this level made their debut in an LTS is beyond me. /rantoff

hlmjr

As I suspected, I was going down the wrong path. The issue is QTBUG-74326, and resolved in this patch which is scheduled for Qt 5.12.3.

It doesn't seem to be a perfect fix as it corrects the system library detection for me but breaks linking QtWebEngine.

Antiheld

@hlmjr said in Qt 5.12.2 Raspberry Pi X11:

As I suspected, I was going down the wrong path. The issue is QTBUG-74326, and resolved in this patch which is scheduled for Qt 5.12.3.

It doesn't seem to be a perfect fix as it corrects the system library detection for me but breaks linking QtWebEngine.

I tried to apply the patch, however it changed nothing. Can you explain how you did it? There's no explanation online on how to apply such patches manually, only via git when having previously cloned the git repo. I wanted to apply it to the current source release (qt-everywhere-src-5.12.2), though.

I myself am currently trying to cross-compile Qt 5.12.2 for Raspberry Pi 3 B+.
Weirdly enough I have to configure with -device linux-rasp-pi-g++ to get EGLFS to work, might that be the problem?

hlmjr

@Antiheld True, it is difficult to get a patch from those changesets they way they're displayed in gerrit. I created one myself you can obtain from https://www.sky-meyg.com/downloads/rpi-qt5.12-configure.patch. Apply it with patch -p0 < rpi-qt5.12-configure.patch in your Qt source directory.

Antiheld

@hlmjr Thank you for your quick answer!
Weirdly enough it doesn't change anything for me. Maybe I'm doing something wrong.
For now EGLFS will have to suffice, I guess.
Thank you anyway!

silicon

@Lashc said in Qt 5.12.2 Raspberry Pi X11:

12.2 to my Raspberry Pi 3 B+ f

Hello,
I'm also using same setup RPi 3B+ with Qt5.12.2
facing the same issue with xcb.
i've tried all above mentioned solutions nothing works for me.
Could you solve the issue?

Thanks in advance.