Blacklisting an Input Device

Peter Hutterer peter.hutterer at
Wed Dec 29 15:28:02 PST 2010

On Wed, Dec 29, 2010 at 05:23:08PM -0600, Gabriel M. Beddingfield wrote:
> Hi Peter,
> On Wednesday, December 29, 2010 04:55:55 pm Peter Hutterer 
> wrote:
> > > However, I wonder if the attached patch to
> > > xf86-input-evdev might be appropriate.
> [snip]
> > 
> > no, there's a few devices that only have wheel axes and
> > they need to keep working. Note that the "configured as
> > mouse" message is probably misleading, it simply means
> > that evdev will use the relative axes. your problem is
> OK.
> > that 0/0 coordinates are sent and we need to figure out
> > why. do you see the 0/0 coordinates when you run evtest
> > against the device? if so, then the kernel driver needs
> > fixing (or quirking). otherwise, it's either evdev or
> > the server.
> Well, it's supposed to send data... it's just not supposed 
> to be /coordinate/ data for the X Server.  It's supposed to 
> be MIDI-related data for jog wheels and volume levels and 
> whatnot.  It wasn't a problem in older versions of X11 
> because it would be ignored (since it didn't have axes AND 
> buttons).

what's the evtest output then? the driver shouldn't post random axes as x/y.

> So, looks like I need to change the kernel driver... to 
> prevent it from appearing to the X Server as any sort of HID 
> device.

mind you, the better option still seems to be to blacklist the device for
evdev using xorg.conf snippets. other processes may want to use the device
as HID device.


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