README.md

Script to configure displays via EDID rather than outputs with xrandr

Sometime output designations change in xrandr. Particular when using a docking station (e.g., a Lenovo Thunderbolt 4 Dock). In those cases scripts that use output names to configure a display setup fail. This script provides function to use a screens.ini file (see example) with EDIDs rather than output names.

# get EDIDs for output names
bash screens.sh map

# configure displays according to `config.ini`
bash screens.sh set

Hints

Screens stay black

Things to try:

• Try to plug in your docking station on another USB-C port.
• Suspend and wake up with the docking station attached.

TODO

• allow to switch between configs
• auto config
• fix that annyoing black screen bug (sometimes screens just stay black)

screens.ini

00ffffffffffff0010ac8c4255394241 --mode 0x58 --crtc 0 --rotate normal
00ffffffffffff0010ac7c424c544742 --mode 0x58 --crtc 0 --rotate normal --right-of 00ffffffffffff0010ac8c4255394241
00ffffffffffff0010ac7b424c314842 --mode 0x58 --crtc 1 --rotate right  --right-of 00ffffffffffff0010ac7c424c544742
00ffffffffffff004c835a4100000000 --mode 0x61 --crtc 2 --rotate normal --right-of 00ffffffffffff0010ac7b424c314842

screens.sh

#!/bin/bash

function get_port_edid_map {
    xrandr --props | awk '/DP.* connected/{PORT=$1} /EDID/{EDID=1; next} //{if (EDID==1) printf "%s\t%s\n",  PORT, $1; EDID=0}'
}

function get_outputs {
    echo "$(get_port_edid_map)" | cut -f 1
}

function get_edids {
    echo "$(get_port_edid_map)" | cut -f 2
}

function edid_to_port {
    port=$1
    echo "$(get_port_edid_map)" | grep $port | cut -f 1
}

function replace_edid_with_port {
    string=$1
    #echo "$string"
    for edid in $(get_edids); do
        port=$(edid_to_port $edid)
        #echo "Replace: $edid > $port"
        string=$(echo "$string" | sed s/$edid/$port/g)
        #echo "$string"
    done
    echo $string
}

function off {

    MAIN_SCREEN=${1:-eDP-1}
    MAIN_MODE=${2:-0x61}

    for o in $(get_outputs); do
       echo $o
       xrandr --output $o --off
    done
}

function main {
    MAIN_SCREEN=${1:-eDP-1}
    MAIN_MODE=${2:-0x61}
    xrandr --output $MAIN_SCREEN --mode $MAIN_MODE
}

function reset {
    off
    sleep 5
    main ${@}
}


# print modes: xrandr --verbose | grep MHz | sort --key 3 --numeric-sort --reverse | uniq
# seach modes: xrandr --verbose | egrep '^[^[:space:]]|241.500MHz'

function set_screens {

    config=$(cat screens.ini)

    echo "Checking whether EDIDs in config exist:"
    echo "---------------------------"
    while read line; do
        echo "$line"
        edid=$(echo "$line" | cut -d " " -f 1)
        port=$(edid_to_port $edid)
        if [[ "$port" == "" ]]; then
            echo -e "ERROR: Invalid config. Unknown EDID: $edid"
            return
        fi
    done <<< "${config}"
    echo "---------------------------"

    echo "Turning off all screens" 
    sleep 1
    off
    sleep 3

    echo ""
    echo "Turning screens back on:"
    echo "---------------------------"
    while read line; do
        replaced=$(replace_edid_with_port "$line")
        cmd="xrandr --output $replaced"
        echo "$cmd"
        $cmd
        sleep 3
    done <<< "${config}"
    echo "---------------------------"
}

if [[ "$1" == "reset" ]]; then
    reset ${@:2}
elif [[ "$1" == "set" ]]; then
    set_screens
elif [[ "$1" == "map" ]]; then
    get_port_edid_map
else
    echo "Unknown command: $1"
fi