eGPU detection and Xorg configuration script

egpu-detect.service

[Unit]
Description="eGPU Xorg configuration"
Before=display-manager.service

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/usr/local/bin/egpu-detect

[Install]
RequiredBy=display-manager.service

egpu-detect.sh

#!/bin/sh

TIMEOUT=10
BUS='0000:08:00.0'
VID='0x1002'
PID='0x73ff'
CONFIG_PATH='/etc/X11/xorg.conf.d/00-egpu.conf'

bus_path="/sys/bus/pci/devices/${BUS}"


rm -rf "${CONFIG_PATH}"


udevadm wait -t 1 "${bus_path}"
egpu_not_there=$?

if  [ ${egpu_not_there} -eq 1 ] || \
    [ "$(cat "${bus_path}/vendor")" != "${VID}" ] || \
    [ "$(cat "${bus_path}/device")" != "${PID}" ]
then
    echo "eGPU not detected"
    exit 0
fi

echo "eGPU detected"


udevadm wait -t ${TIMEOUT} "/dev/dri/by-path/pci-${BUS}-card"

card_path="$(find "${bus_path}/drm/" -maxdepth 1 -name "card*" -print -quit)"
monitor_detect="$(find "${card_path}" -name "status" \
    -execdir sh -c '[ "$(cat "$0")" = "connected" ] && echo "1"' {} \;)"

if [ -n "${monitor_detect}" ]
then
    echo "Monitor plugged in"
    cat > ${CONFIG_PATH} <<EOF
Section "ServerFlags"
	Option "AutoAddGPU" 	"Off"
EndSection

Section "Device"
	Identifier 			"DeviceEGPU"
	Driver 				"amdgpu"
	BusID 				"PCI:8:0:0"
	Option "TearFree" 		"On"
	Option "Monitor-HDMI-A-1" 	"MonitorMain"
	Option "Monitor-DisplayPort-6" 	"MonitorSub"
EndSection

Section "Monitor"
	Identifier 		"MonitorMain"
	Option "Primary" 	"On"
	Option "PreferredMode" 	"1920x1080"
	Option "Position" 	"1200 420"
EndSection

Section "Monitor"
	Identifier 		"MonitorSub"
	Option "Primary" 	"Off"
	Option "PreferredMode" 	"1920x1200"
	Option "Rotate" 	"left"
	Option "Position" 	"0 0"
EndSection

Section "Screen"
	Identifier 	"ScreenMain"
	Device 		"DeviceEGPU"
	Monitor 	"MonitorMain"
	SubSection "Display"
		Depth 24
		Virtual 8192 8192
	EndSubSection
EndSection
EOF

else
    echo "No monitor plugged in"
    cat > ${CONFIG_PATH} <<EOF
Section "Device"
	Identifier 	"DeviceEGPU"
	Driver 		"amdgpu"
	BusID 		"PCI:8:0:0"
EndSection

Section "Device"
	Identifier 	"DeviceIGPU"
	Driver 		"amdgpu"
	BusID 		"PCI:196:0:0"
	Option "TearFree" "On"
EndSection

Section "Screen"
	Identifier 	"ScreenMain"
	Device 		"DeviceIGPU"
	GPUDevice 	"DeviceEGPU"
	SubSection "Display"
		Depth 24
		Virtual 8192 8192
	EndSubSection
EndSection
EOF

fi