My basic question is: How do I set an xinput property on another user's X server?

I have a udev rule that runs a custom script when a particular USB device (a mouse) connects. The script runs, and all it does is set an xinput property, thus:

The xinput command is correct, it works when I run it in a terminal under X. However, it does not work when run from udev, ie. outside of X. I've tried prepending the DISPLAY environment (and even XAUTHORITY). My Google-fu is stretched to the limit on this one.

(I know about setting the mouse sensitivity et al via various GUIs, but I swap the mouse between two computers often and the above configured property resets itself whenever the mouse is reconnected, hence the udev rule. xset doesn't work for this, xinput does.)

Thank you.

It won't.

The X server has to be active for the user (not gdm/kdm/...) before the xinput can be initialized, and the process has to have the authority to connect to the Xserver to set things like that up. Udev runs as root, and doesn't have the authority.

Now if it is already hooked up you CAN add the input to the X configuration. I'm not sure what would happen if the device wasn't hooked up though - hopefully, the feature would just not work, but the worst thing that would happen is that the X server aborts, and users would be unable to log in.

OK, thanks. The device will always be hooked up when my udev rule is triggered. After all, it's the hooking up that triggers it. How can I "add the input to the X configuration"? Or have I misunderstood that bit?

My next move would be to detect the particular property changing from my 1.8 value and trigger something to change it back. My final move would be to just have a cron job that sets it every few seconds, regardless.

There is an xorg.conf.d directory. The directory contains segments of the full xorg.conf file that has all the optional modules included. The reason it is in segments is to allow you to override only those parts of the default that are causing problems, without having to have the full (and elaborate) configuration file.

Doh! That did the trick. For some reason, I was under the impression that the sensitivity would still change when plugged even after X was started. Thank you for the help.