Getting involved in XInput hotplug development?

Enleth enleth at
Sun Feb 4 13:28:07 PST 2007

As someone might be interested in that, there are two little pieces of code I 
wrote, primarily for my personal use (yes, I do really need this hotplug that 
much), and some thoughts:

1. A patch for xserver, hw/xfree86/common/xf86Xinput.c, that prevents crashes 
caused by DBUS messages without an identifier or a driver specified, both 
cases result in a SIGSEV (no driver - crash a few lines down, no identifier - 
one function call further from there, I can't recall the backtrace now).

2. A simple Python script that relays HAL DeviceAdded events to Xserver, 
currently supporting mice and Wacom tablets (I had to adapt the driver to the new XInput code, the patch will be on its way 
to their mailing list shortly). I know it's ugly because it uses evdev's 
Device option, but works. It takes the display number as an argument, e.g. 
python 0. The identifier string should probably be generated in a 
smarter way to avoid messing things up when two identical devices get plugged 
in at the same time, but that's something to do later.

Still, there is one thing that concerned me while writing the script, namely 
removing the devices. The server expects numerical device identifier, the 
script as it is now has no way of knowing it. There could be a few different 
ways to get around this, but I didn't try to implement any of them, as I'd 
like, even in something I write for myself, to do that the way 
developers see it, so it's either useful for everyone, or just easy for me to 
switch to something more "official" later on.

Remigiusz "Enleth" Marcinkiewicz, enleth at
JID enleth at
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import sys
import dbus
import gobject
if getattr(dbus, 'version', (0,0,0)) >= (0,41,0):
    import dbus.glib

display = sys.argv[1]
dbus_x_name = 'org.x.config.display' + display
dbus_x_object = '/org/x/config/' + display
dbus_x_intf_input = 'org.x.config.input'

dbus_hal_name = 'org.freedesktop.Hal'
dbus_hal_object = '/org/freedesktop/Hal/Manager'
dbus_hal_intf_manager = 'org.freedesktop.Hal.Manager'
dbus_hal_intf_device = 'org.freedesktop.Hal.Device'

bus = dbus.SystemBus()

xorg_obj = bus.get_object(dbus_x_name,dbus_x_object)
xorg = dbus.Interface(xorg_obj,dbus_x_intf_input)

hal_obj = bus.get_object(dbus_hal_name,dbus_hal_object)
hal = dbus.Interface(hal_obj,dbus_hal_intf_manager)

def SendAddRequest(identifier, device, driver = 'evdev', isCore = 'true', options = []):
	print "Sending device add message."

def AddMouse(dev):
	print "Adding a mouse."
	name = dev.GetProperty('input.product',  dbus_interface=dbus_hal_intf_device)
	device = dev.GetProperty('input.device',  dbus_interface=dbus_hal_intf_device)
	print "Added a mouse."

def AddTablet(dev):
	print "Adding a tablet."
	name = dev.GetProperty('input.product', dbus_interface=dbus_hal_intf_device)
	device = dev.GetProperty('input.device', dbus_interface=dbus_hal_intf_device)
	print "Added a tablet."

def dev_add_callback(udi):
	print "HAL: a device was added."
	dev = bus.get_object('org.freedesktop.Hal',udi)
	if not dev.PropertyExists('info.category',  dbus_interface=dbus_hal_intf_device):
		print "No info.category, ignoring."
	print dev.GetProperty('info.category', dbus_interface=dbus_hal_intf_device)
	if dev.GetProperty('info.category', dbus_interface=dbus_hal_intf_device) == 'input':
		print "Input device detected."
		if not dev.PropertyExists('info.capabilities', dbus_interface=dbus_hal_intf_device):
		capabilities = set(dev.GetProperty('info.capabilities', dbus_interface=dbus_hal_intf_device))
		if 'input.mouse' in capabilities:
		if 'input.tablet' in capabilities:
		print "Nothing interesting, ignoring."


mainloop = gobject.MainLoop()

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