hotplug example?

Chuck Robey chuckr at
Mon Jun 16 10:52:32 PDT 2008

Hash: SHA1

Peter Hutterer wrote:
> On Mon, Jun 16, 2008 at 09:29:52AM -0400, Chuck Robey wrote:
>> Could I get the name of any input driver that implements hotplugging via hal &
>> dbus?  I need to implement this now in my driver, but I'm unclear (even in
>> general terms) what it is I'm accomplishing.
> Just look at xf86-input-evdev. The driver simply needs to clean up after
> itself in UnInit and DeviceProc(..., DEVICE_CLOSE). The actual hotplugging is
> done by the server, the driver doesn't really know if it's hotplugged or
> started on init.
> To get hotplug working, hal needs to send a notification to the xserver when
> the device appears. xserver/config/x11-input.fdi has the magic for that, you
> can change keys for your device to use a different driver.
> If you can't use hal for some reason, you need to compile your server with
> --enable-config-dbus and then send the appropriate commands (documented in
> xserver/config/dbus-api).

Thanks, Peter.  Right now, I am reading the Hal spec (I finished dbus and
policykit), because I think maybe it's not fully implemented in FreeBSD for USB,
and I want to verify (and possibly fix this).  Soon as I make sure it's working
on FreeBSD as well as it does on Linux, I will begin to add it to my file, which
I've named uclogic (  I am determined it should be a completely
implemented driver, which is why I suddenly am after dbus & hal (I finally saw
they were needed for a complete job).

One thing I'm probably missing, though: I only know about the 6 inputs (3
buttons, X, Y, and Tip Pressure).  I've heard about things like 3D or 4D
features, and some sort of hot spot menus, but I haven't found any good
description of how these work.  I'm personally disabled, so I can't go out and
try them in stores... if anyone out there knows of special features like these.
that ought to be implemented in an Xinput driver, I would be extremely grateful
for info about those features.  Not code, because if I know what it is, I really
should be able to do the implementation myself, I think.  It's the idea I'm missing.

Although, without those additions, it's still a really nice, cheap graphic
tablet, selling for about $60 for an 8" by 6" model, under a whole batch of
different names.  I know about WizardPen, MousePen, and LaPazz, but there are
more, I'm sure of this, all having UC-Logic show up in the USB probing.

> Cheers,
>   Peter

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