Use dummy driver in headless Xorg

config/X11/Xsession.d/60virtualgl

@@ -1,11 +1,7 @@
 #!/bin/sh
 
 if [ -z "${VGL_DISPLAY-}" ]; then
-	# Use the dummy X server if it is enabled
-	if [ "${SERVICE_XORG_HEADLESS_ENABLED:?}" = 'true' ]; then
-		export VGL_DISPLAY=:0.0
-	else
-		# Otherwise try to use the EGL backend
+	# Try to use the EGL backend
 	for card in /dev/dri/card*; do
 		if /opt/VirtualGL/bin/eglinfo -B "${card:?}" 2>/dev/null; then
 			export VGL_DISPLAY="${card:?}"
@@ -17,4 +13,3 @@ if [ -z "${VGL_DISPLAY-}" ]; then
 		export VGL_DISPLAY="${DISPLAY:?}"
 	fi
 fi
-fi

config/X11/xorg.conf.d/10-headless.conf

@@ -1,30 +1,20 @@
 Section "Module"
-	Load "xorgxrdp"
-EndSection
-
-Section "ServerLayout"
-	Identifier "ServerLayout0"
-	Screen "Screen0"
+	Disable "glx"
 EndSection
 
 Section "ServerFlags"
 	Option "DefaultServerLayout" "ServerLayout0"
 	Option "DontVTSwitch" "on"
+	Option "PciForceNone" "on"
 	Option "AutoAddDevices" "off"
 	Option "AutoAddGPU" "off"
 EndSection
 
-Section "Monitor"
-	Identifier "Monitor0"
-	VendorName "Unknown"
-	ModelName "Unknown"
-EndSection
-
-Section "Device"
-	Identifier "Device0"
-	Driver "xrdpdev"
-	Option "DRMDevice" "/dev/dri/renderD128"
-	Option "DRI3" "1"
+Section "ServerLayout"
+	Identifier "ServerLayout0"
+	Screen "Screen0"
+	InputDevice "Keyboard0"
+	InputDevice "Mouse0"
 EndSection
 
 Section "Screen"
@@ -35,3 +25,26 @@ Section "Screen"
 		Modes "800x600"
 	EndSubSection
 EndSection
+
+Section "Monitor"
+	Identifier "Monitor0"
+	VendorName "Unknown"
+	ModelName "Unknown"
+EndSection
+
+Section "Device"
+	Identifier "Device0"
+	Driver "dummy"
+EndSection
+
+Section "InputDevice"
+	Identifier "Keyboard0"
+	Driver "void"
+	Option "CoreKeyboard" "true"
+EndSection
+
+Section "InputDevice"
+	Identifier "Mouse0"
+	Driver "void"
+	Option "CorePointer" "true"
+EndSection