Using BLFS and Arch Linux Have Error qt.qpa.xcb: could not connect to display

[glanzkaiser]

Dear Qt Forum,
Sorry if I bother you all. I am learning to create OS with KDE as my Desktop Environment using Qemu/KVM, my laptop is using CAELinux but I use ArchLinux as the virtual OS / main OS for my Linux From Scratch experimental OS.

I already at this stage (https://www.linuxfromscratch.org/blfs/view/11.0/kde/plasma-all.html), I am using /opt/kf5 as my prefix but when I want to try it by running:
"startx"
an error window showed up saying:
'ksplashqml closed unexpectedly
Details: ksplashqml PID: 9212 Signal: Segmentation fault(11)'

I asked BLFS forum it stated that I need to check environment variables, I already put it correctly according to the BLFS book.
Then I check :
"qml --version"
It stated:
'qt.qpa.xcb: could not connect to display
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.'

I guess my Qt is not installed right is it true? or I need to download a package related to "xcb" or do I need to do anything else to fix this?

Thank You

[jsulm]

@glanzkaiser said in Using BLFS and Arch Linux Have Error qt.qpa.xcb: could not connect to display:

'qt.qpa.xcb: could not connect to display

Looks like you do not have X server running?

[glanzkaiser]

I have make Xorg working in the past at X Window Environment stage.
How to fix this or check that the X server is running?
Thanks

[jsulm]

@glanzkaiser You can try to run any other X application.
Also, what does

echo $DISPLAY

output?

[glanzkaiser]

it returns nothing, I have to set this one then. I try to do this just now:
" export DISPLAY=0"
then I check again:
"qml --version"
It returns a lot of strings and at the end:
'Got keys from plugin meta data ("xcb")
QFactoryLoader::QFactoryLoader() checking directory path "opt/kf5/lib/plugins/kcms/platforms"...
QFactoryLoader::QFactoryLoader() checking directory path "opt/qt5/bin/platforms"...
loaded library "/opt/qt5/plugins/platforms/libqxcb.so"
qt.qpa.xcb: could not connect to display 0
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.'

What value should I set for $DISPLAY to fix the ksplashqml error when running startx to run KDE Plasma?

Thanks jsulm

[jsulm]

@glanzkaiser said in Using BLFS and Arch Linux Have Error qt.qpa.xcb: could not connect to display:

it returns nothing

Then X server is not running. Setting DISPLAY manually will not help. You need to make sure X server is running.

[glanzkaiser]

@jsulm said in Using BLFS and Arch Linux Have Error qt.qpa.xcb: could not connect to display:

X server is not running.

So I start X Server by using Fluxbox DE then I check:
"qml --version"
it returns :
'Qml runtime 5.15.2'

Then I type:
"echo $DISPLAY"
returns:
':0.0'

then I edit the ~/.xinitrc into:
"dbus-launch --exit-with-session $KF5_PREFIX/bin/startplasma-x11"
only one line, then I type on xterm inside Fluxbox:
"startx"
the cursor changed but the screen is black, no more ksplashqml error shown. Should I consult with KDE team for this or is it because I am missing something?

Thanks.

[jsulm]

@glanzkaiser said in Using BLFS and Arch Linux Have Error qt.qpa.xcb: could not connect to display:

then I type on xterm inside Fluxbox:
"startx"

But X server is already running, right?
You should first exit Fluxbox.

[glanzkaiser]

Yes I logout and in the LXDM I choose "Plasma (X11)" then it hangs but the cursor of the mouse changing shape.