Linux CEC Setup + Monitoring + Remote Control Keymap for Pulse-Eight CEC Adapter or DisplayPort

_install.sh

#!/bin/sh

# Resources:
# - https://wiki.archlinux.org/title/HDMI-CEC
# - https://man.archlinux.org/man/extra/v4l-utils/rc_keymap.5.en
# - https://man.archlinux.org/man/extra/v4l-utils/ir-keytable.1.en
# - https://www.freedesktop.org/software/systemd/man/latest/systemd.unit.html
# - https://www.freedesktop.org/software/systemd/man/latest/systemd.service.html

# Make sure to replace card1-HDMI-A-2 with your own connector in: cec0-daemon-autostart.rules

if [ "$(id -u)" -ne 0 ]; then
    echo "This script must be run as root"
    exit 1
fi

# Install dependencies
dnf install -y v4l-utils linuxconsoletools rc-tools

# Install cec-daemon
install -vDm755 cec-daemon /usr/local/bin

# Setup Pulse-Eight CEC Adapter (if present)
# - Attaches /dev/ttyACM0 to /dev/cec0
# - CEC via display port is attached automatically on linux
if lsusb -v | grep --silent Pulse-Eight; then
    install -vDm644 [email protected] /etc/systemd/system/
    install -vDm644 pulse8-cec-autoattach.rules /etc/udev/rules.d/
fi

# Configure CEC
{
    install -vDm644 [email protected] /etc/systemd/system/
    install -vDm644 cec0-daemon-autostart.rules /etc/udev/rules.d/
}

# Setup remote control keymap
{
    install -vDm644 cec.toml /etc/rc_keymaps/cec.toml

    ir-keytable --sysdev rc0 --read |
        sed -E 's/^scancode //;s/ \(.+\)$//;s/(KEY_[A-Z0-9]+)/"\1"/' 2>/dev/null \
            >>/etc/rc_keymaps/cec.toml

    install -vDm644 rc0-keymap-autoapply.rules /etc/udev/rules.d/
}

# reload systemd and udev
{
    systemctl daemon-reload
    udevadm control --reload-rules
    udevadm trigger
}

# Monitor cec daemon with:
# journalctl -f -u [email protected]"

# Monitor adapter with:
# journalctl -f -u [email protected]"

# Monitor remote control events with:
# ir-keytable --sysdev rc0 --test

_uninstall.sh

#!/bin/bash

if [ "$(id -u)" -ne 0 ]; then
    echo "This script must be run as root"
    exit 1
fi

rules=(
    /etc/udev/rules.d/pulse8-cec-autoattach.rules
    /etc/udev/rules.d/cec0-daemon-autostart.rules
    /etc/rc_keymaps/cec.toml
    /etc/udev/rules.d/rc0-keymap-autoapply.rules
)

services=(
    /etc/systemd/system/[email protected]
    /etc/systemd/system/[email protected]
)

binaries=(
    /usr/local/bin/cec-daemon
)

# remove rules
for path in "${rules[@]}"; do
    if [ -f "$path" ]; then
        echo "Removing: $path"
        rm -f "$path"
    else
        echo "Skipping (not found): $path"
    fi
done

# stop services
for path in "${services[@]}"; do

    service_basename=$(basename "$path")

    if [[ "$path" == *"@.service" ]]; then

        search="${service_basename/@.service/@*.service}"
        base="${service_basename/@.service/}"

        names=$(
            systemctl list-units "$search" --all |
                grep "$base" | xargs | cut -d ' ' -f1
        )

        for name in $names; do
            echo "Stopping $name"
            systemctl stop "$name"
        done
    else
        echo "Stopping $name"
        systemctl stop "$name"
    fi

    echo "Removing: $path"
    rm -f "$path"
done

# remove binaries
for path in "${binaries[@]}"; do
    if [ -f "$path" ]; then
        echo "Removing: $path"
        rm -f "$path"
    else
        echo "Skipping (not found): $path"
    fi
done

# reload systemd and udev
systemctl daemon-reload
udevadm control --reload-rules

cec-daemon

#!/bin/bash

# Configures the CEC adapter as playback device
# and monitors output to set it as the active source whenever the root device selects it

CONNECTOR=$1
HOSTNAME=$(hostnamectl hostname)

EVENTS=(
    "SET_STREAM_PATH"
    "STANDBY"
)

function register_as_playback() {
    cec-ctl "--osd-name=$HOSTNAME" --playback "--phys-addr-from-edid=/sys/class/drm/$CONNECTOR/edid"
}

function get_phys_addr() {
    cec-ctl --skip-info --physical-address
}

function set_as_active_source() {
    cec-ctl --skip-info --active-source "phys-addr=$1" >/dev/null
}

function on_standby() {
    echo "-- STANDBY --"
}

function on_active() {
    echo "-- ACTIVE --"
}

function on_unactive() {
    echo "-- UNACTIVE --"
}

function on_set_stream_path() {
    if [[ $1 != $(get_phys_addr) ]]; then
        on_unactive
        return
    fi

    set_as_active_source "$1"
    on_active
}

function handle_event() {

    local line=$1
    local event=$2

    if [[ "$line" != *"$event"* ]]; then return 1; fi

    case $event in
    "STANDBY")
        on_standby
        ;;
    "SET_STREAM_PATH")
        IFS= read -r line
        addr=$(echo "$line" | cut -d ':' -f2 | xargs)
        _line=""
        on_set_stream_path "$addr"
        ;;
    *)
        echo "Unknown event: $event"
        ;;
    esac

    return 0
}

function monitor() {
    _last_line=""
    cec-ctl --skip-info --monitor --ignore all,poll | while IFS= read -r _line; do

        if [[ "$_line" != "$_last_line" ]]; then
            for event in "${EVENTS[@]}"; do
                handle_event "$_line" "$event" && break
            done
        fi

        _last_line=$_line

    done
}

register_as_playback
monitor

cec.toml

[[protocols]]
name = "CEC Remote Control"
protocol = "cec"
[protocols.scancodes]
# Execute the following command and insert the output here:
#
# ir-keytable --sysdev rc0 --read 2>/dev/null | sed -E 's/^scancode //;s/ \(.+\)$//;s/(KEY_[A-Z0-9]+)/"\1"/'
#
# It should look like this:
# 0x0000 = "KEY_ENTER"
# 0x0001 = "KEY_UP"
# 0x0002 = "KEY_DOWN"
# 0x0003 = "KEY_LEFT"
# 0x0004 = "KEY_RIGHT"
# ...
#
# You can then modify the events as needed

cec0-daemon-autostart.rules

SUBSYSTEM=="cec" KERNEL=="cec0" ACTION=="add" TAG+="systemd" ENV{SYSTEMD_WANTS}="[email protected]"

[email protected]

[Unit]
# Should be called as "[email protected]" or similar
Description=Configure CEC adapter as playback device and monitor output to set it as the active source whenever the root device selects it
AssertPathExists=/sys/class/drm/%i/edid
BindsTo=dev-cec0.device

[Service]
Type=exec
ExecStart=/usr/local/bin/cec-daemon "%i"
Restart=always
RestartSec=5
ProtectSystem=strict
ProtectHome=true

[email protected]

[Unit]
# Should be called as "[email protected]" or similar
Description=Configure USB Pulse-Eight serial device at %I
ConditionPathExists=%I

[Service]
Type=forking
ExecStart=/usr/bin/inputattach --daemon --pulse8-cec %I
ProtectSystem=strict
ProtectHome=true

pulse8-cec-autoattach.rules

SUBSYSTEM=="tty" ACTION=="add" ATTRS{manufacturer}=="Pulse-Eight" ATTRS{product}=="CEC Adapter" TAG+="systemd" ENV{SYSTEMD_WANTS}="pulse8-cec-attach@$devnode.service"

rc0-keymap-autoapply.rules

SUBSYSTEM=="rc" ACTION=="add" ENV{DRV_NAME}=="cec" RUN+="/usr/bin/ir-keytable --sysdev $devpath --write /etc/rc_keymaps/cec.toml"