Skip to content

CHORE: fix LED flicker in setup-pi (disable sound, isolate core) #3

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
hahuang65 merged 1 commit into from
Jun 18, 2026
Merged

CHORE: fix LED flicker in setup-pi (disable sound, isolate core) #3

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
30 changes: 29 additions & 1 deletion bin/setup-pi.sh
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -77,11 +77,39 @@ sudo mkdir -p /var/lib/jetset/logos
sudo chown "$(whoami):$(whoami)" /var/lib/jetset/logos
uv run python scripts/download_logos.py || echo "(logo download incomplete — re-run later)"

# 7. Install + enable the systemd service (runs on boot)
# 7. Reduce LED panel flicker. Two causes, both fixed here (idempotent; both
# take effect on the next reboot):
# a) Onboard sound: the Adafruit HAT drives the panel's PWM timing on the
# same hardware snd_bcm2835 uses, so leaving sound enabled is the most
# common flicker source. Blacklist the module and turn audio off.
# b) CPU contention: the matrix refresh thread runs on core 3; isolating it
# (isolcpus=3) stops the scheduler from interrupting it with other work.
echo "=== Reducing LED flicker (disable sound, isolate core 3) ==="
echo "blacklist snd_bcm2835" | sudo tee /etc/modprobe.d/blacklist-rgb-matrix.conf >/dev/null

BOOT_CONFIG=/boot/firmware/config.txt
[ -f "$BOOT_CONFIG" ] || BOOT_CONFIG=/boot/config.txt
if [ -f "$BOOT_CONFIG" ]; then
if grep -q "^dtparam=audio=on" "$BOOT_CONFIG"; then
sudo sed -i "s/^dtparam=audio=on/dtparam=audio=off/" "$BOOT_CONFIG"
elif ! grep -q "^dtparam=audio=off" "$BOOT_CONFIG"; then
echo "dtparam=audio=off" | sudo tee -a "$BOOT_CONFIG" >/dev/null
fi
fi

# cmdline.txt must stay a single line; append isolcpus to line 1 only if absent.
BOOT_CMDLINE=/boot/firmware/cmdline.txt
[ -f "$BOOT_CMDLINE" ] || BOOT_CMDLINE=/boot/cmdline.txt
if [ -f "$BOOT_CMDLINE" ] && ! grep -q "isolcpus=" "$BOOT_CMDLINE"; then
sudo sed -i "1 s/\$/ isolcpus=3/" "$BOOT_CMDLINE"
fi

# 8. Install + enable the systemd service (runs on boot)
echo "=== Installing jetset systemd service ==="
bash bin/install-service.sh
sudo systemctl restart jetset

echo "=== Setup complete! The jetset service is enabled and running. ==="
echo " Logs: journalctl -u jetset -f"
echo " (foreground debug run: \`make debug-pi\` — stop the service first)"
echo " NOTE: reboot once to apply the sound/flicker fix: sudo reboot"
Loading