Observed UI flickering on ARM target

Praveen.Illa

@SGaist Please find below comments
You need to give more information about your device, its screen, etc.
Kernel Version: 4.19.94
Processor: ARM 4378
Resolution: 1024*600
Also, how are you starting your application ? ./ui -platform eglfs
Are you using something like Wayland ? No
What parameters are you using ?
cat /etc/environment
QT_QPA_EGLFS_INTEGRATION=eglfs_kms
EDITOR=vi
HUSHLOGIN=FALSE
QT_WAYLAND_SHELL_INTEGRATION=wl-shell
USER=root
PWD=/home/root
HOME=/home/root
QT_QPA_EGLFS_KMS_CONFIG=/etc/qt5/eglfs_kms_cfg.json
SSL_CERT_FILE=/etc/ssl/certs/ca-certificates.crt
TSLIB_TSDEVICE=/dev/input/touchscreen0
QT_QPA_EGLFS_PHYSICAL_WIDTH=256
MAIL=/var/spool/mail/root
SHELL=/bin/sh
TERM=vt102
TMOUT=900
SHLVL=1
QT_QPA_EGLFS_ALWAYS_SET_MODE=1
LOGNAME=root
PATH=/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin
PS1=\u@\h:\w$
QT_QPA_EGLFS_PHYSICAL_HEIGHT=150

Please let me know if you required any more details. Thank You

SGaist

Are you using a Texas Instruments evaluation board ?

Praveen.Illa

@SGaist
We are running Qt on customized TI AM437x boards. Please find below board details and SW components

Kernel Version: 4.19.94
SOC: TI AM4378
Resolution: 1024*600
Screen size: 7" & 10"
GPU: SGX530 Graphics Engine

SGaist

Could it be that you have the tty cursor that is blinking through your UI ?

Praveen.Illa

@SGaist
I have disabled the tty cursor. Still, I could see flickering on UI.
Below is the code, I have commented
.

SGaist

Would it be possible to see the video of the flickering ?

Praveen.Illa

@SGaist
I am not able to attach the video in this forum. I am getting below error

So, I am attaching the image

Please refer to the attached image where the image in top right corner is the image of previous screen. It is displaying in fraction of seconds and goes off., and this flickering happens continuously

SGaist

Is it a widget or Qt quick application ?

JoeCFD

@Praveen-Illa add 10ms or maybe 5ms delay to this widget display to see if it helps. Also you need to call update explicitly if this widget is customized. Qt widgets update is not very clean on touch screen.

Praveen.Illa

@SGaist
It is a Qt Quick application

SGaist

Do you have the same issue with a minimal default application ?

Praveen.Illa

@SGaist Thank you for your response
I have resolved this issue by changing the graphics driver.
I am attaching the link below for others who are facing this kind of problem.

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1060753/am4378-flickering-issue-on-qt-with-eglfs-instance

PrajwalG99

Hi @SGaist , I'm encountering a similar issue in our application — there's a brief flicker with a light white background whenever a button is clicked.

Here are the details of the machine -

Device Information

Kernel Version: 6.11.0-24-generic
Processor: Intel® Core™ i5-4570TE CPU @ 2.70GHz (4 threads, 2 cores, VT-x supported)
Resolution: 3840×2160 @ 60Hz (4K UHD)
SOC: Not explicitly listed, but the CPU is part of Intel's Haswell family, typically used in embedded or low-power systems.
GPU: NVIDIA Quadro P1000 (GP107GL), professional-grade graphics card with active nvidia driver
Display Driver: nvidia
Display Interface: X11
OS: Ubuntu 24.04.1 LTS on an x86_64 architecture
Qt: QMake version 3.1, Using Qt version 6.5.3 in /opt/Qt/6.5.3/gcc_64/lib
Application is developed using qt widgets.

Also, how are you starting your application? ./start.sh
Are you using something like Wayland? No, it's - x11
What parameters are you using? -

QMAKE=/opt/Qt/6.5.3/gcc_64/bin/qmake
SHELL=/bin/bash
JAVA_HOME=/usr/local/jdk1.7.0_79
cmake=/usr/local/cmake-3.0.0
QT_PATH=/opt/Qt/6.5.3/gcc_64
mico_home=/sect/package/mico_2.3.13.1
mongodb=/sect/package/rpmapkgs/software/mongodb-v3.4.6/bin
PWD=/home/local
LOGNAME=local
XDG_SESSION_TYPE=tty
glc_home=/sect/package/libGLC
AGLCMSPATH=/home/local/aglcms
HOME=/home/local
LANG=en_US.UTF-8
QT6_PATH=/opt/Qt/6.5.3/gcc_64
SSH_CONNECTION=10.78.235.154 60587 10.78.235.167 22
CATALINA_BASE=/opt/tomcat
SSL_ENABLE=0
LESSCLOSE=/usr/bin/lesspipe %s %s
XDG_SESSION_CLASS=user
TERM=xterm
CATALINA_HOME=/opt/tomcat
LESSOPEN=| /usr/bin/lesspipe %s
USER=local
SHLVL=1
XDG_SESSION_ID=29
QT6_DIR=/opt/Qt/6.5.3/gcc_64/bin/
LD_LIBRARY_PATH=:/opt/Qt/6.5.3/gcc_64/lib:/opt/Qt/6.5.3/gcc_64/lib:/home/local/efps/lib/:/sect/package/mico_2.3.13.1/lib:/sect/package/libGLC/lib:/opt/Qt/6.5.3/gcc_64/lib:/opt/Qt/6.5.3/gcc_64/lib:/home/local/efps/lib/
XDG_RUNTIME_DIR=/run/user/1000
SSH_CLIENT=10.78.235.154 60587 22
DEBUGINFOD_URLS=https://debuginfod.ubuntu.com
mysql_lib=/usr/lib64/mysql
host=bues3-sun9167
XDG_DATA_DIRS=/usr/share/gnome:/usr/local/share:/usr/share:/var/lib/snapd/desktop
PATH=/opt/Qt/6.5.3/gcc_64/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/home/local/aglcms/bin:.:/home/local/bin:/home/local/aglcms/bin:.:/home/local/.local/bin:/home/local/bin:/home/local/aglcms/bin:.:/usr/lib64/mysql:/sect/package/cmake/bin:/usr/local/cmake-3.0.0:/usr/local/jdk1.7.0_79/bin/java:/opt/tomcat:/opt/tomcat:/sect/package/rpmapkgs/software/mongodb-v3.4.6/bin:/opt/Qt/6.5.3/gcc_64/bin/
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
SSH_TTY=/dev/pts/9
_=/usr/bin/printenv

SGaist

@PrajwalG99 hi and welcome to devnet,

Might be a silly question but why not use the Qt 6 version that comes with your distribution ?