Creating a bug report/issue
I have searched the existing open and closed issues
Yes - several topic solutions attempted after searching and recommendations whilst creating post.
Required Information
- DietPi version |
Core = 9, Sub = 16, RC = 3 - Distro version |
trixie 0 - Kernel version | 6.12.34+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.12.34-1+rpt1 (2025-06-26) aarch64 GNU/Linux
- Architecture |
arm64 - SBC model | RPi 4 Model B (aarch64)
- Power supply used | Raspberry Pi 4 Official Adapter
- SD card used | SanDisk Extreme 64GB
Additional Information (if applicable)
- Using 13inch “ZSUS” generic IPS 2160 x 1440 4:3 monitor
- Software title | Chromium Kiosk
- Was the software title installed freshly or updated/migrated? New install
- Can this issue be replicated on a fresh installation of DietPi? Yes
Steps to reproduce
- Fresh install of DietPi
- Follow instructions here to set up Immich Kiosk
- Set dietpi.txt chromium resolution parameters to match display resolution
- Enabled custom HDMI output in config.txt
- Note correct resolution in both text terminal and window manager
- Edited chromium-autostart.sh as follows:
#!/bin/dash
# Autostart script for kiosk mode, based on @AYapejian: https://github.com/MichaIng/DietPi/issues/1737#issue-318697621
# Resolution to use for kiosk mode, should ideally match current system resolution
RES_X=$(sed -n '/^[[:blank:]]*SOFTWARE_CHROMIUM_RES_X=/{s/^[^=]*=//p;q}' /boot/dietpi.txt)
RES_Y=$(sed -n '/^[[:blank:]]*SOFTWARE_CHROMIUM_RES_Y=/{s/^[^=]*=//p;q}' /boot/dietpi.txt)
# Create a temporary xinitrc file to launch unclutter before chromium
cat > /tmp/xinitrc.tmp << 'EOF'
#!/bin/dash
# Hide cursor
unclutter -idle 0 -root &
# Launch Chromium with provided arguments
exec "$@"
EOF
chmod +x /tmp/xinitrc.tmp
# Command line switches: https://peter.sh/experiments/chromium-command-line-switches/
# - Review and add custom flags in: /etc/chromium.d
CHROMIUM_OPTS="--kiosk --window-size=${RES_X:-2160},${RES_Y:-1440} --window-position=0,0"
# If you want tablet mode, uncomment the next line.
#CHROMIUM_OPTS+=' --force-tablet-mode --tablet-ui'
# Home page
URL=$(sed -n '/^[[:blank:]]*SOFTWARE_CHROMIUM_AUTOSTART_URL=/{s/^[^=]*=//p;q}' /boot/dietpi.txt)
# RPi or Debian Chromium package
FP_CHROMIUM=$(command -v chromium-browser)
[ "$FP_CHROMIUM" ] || FP_CHROMIUM=$(command -v chromium)
# Use "startx" as non-root user to get required permissions via systemd-logind
STARTX='xinit'
[ "$USER" = 'root' ] || STARTX='startx'
exec "$STARTX" /tmp/xinitrc.tmp "$FP_CHROMIUM" $CHROMIUM_OPTS "${URL:-https://dietpi.com/}"
Expected behaviour
- Chromium Kiosk should load and display at intended resolution with correct colour depth
Actual behaviour
- Chromium kiosk loads in a 1920x1080 resolution (reported by screen), displaying only the top left corners of images (using vc4-kms-v3d), or a resized image using 1080p coverage of the screen (when using vc4-fkms-v3d
- Colour depth is low, resulting in banding and dithering in both modes
- Switching to 1080p in display mode per other posts causes a fatal x-server error.
Extra details
- Three re-installs thus far with similar effect
- Have also tried to change values based on suggestions here: Non-Interactive RPi Kiosk Improvements with no effect
at the wall, some of it will stick!