#evdev

While getting gamepad input working for Ctesiphon, I decided to figure out how to get my damn keyboard to stop being detected as a damn joystick on Linux, causing endless confusion for Steam and all sorts of games.

Apparently some genius at Ducky didn't fill out the keyboard's HID descriptor properly, and it's wrong in precisely the right way for Linux's generic HID device driver to think the first interface of five on the device is a joystick (I'm not sure why it thinks this, the type is actually Undefined but whatever)

All the information I could find on StartPage pointed me in the direction of "fixing" the broken HID descriptor but the documentation for the format is a huge pain in the butt to find. Along the way though, I established that the interface being detected as a joystick isn't really responsible for anything important so I just made a udev rule to deauthorize it:

This link explains in detail exactly what you need to do (and to boot, it's older than all the advice I've seen regarding the HID descriptor) :

Also, shout out to whoever wrote the man page for udev clearly explaining the difference between ATTRS and ATTR because that was crucial to getting the rule applied correctly.

Bağlar evden eve Nakliyat

There’s been a change in the evdev driver for xorg in the latest ubuntu update that seems to stop monoprice tablets from working correctly.

The effect is that the tablet appears to be working as far as clicking goes but all pressure sensitivity no longer functions. Taps with the pen seem to work fine.. it clicks as it were but can’t draw in krita at all.

After a fair bit of testing with different computers, distros, I came across this incredibly useful guide from the excellent DIGImend project on troubleshooting input issues.

I was getting the pressure reports all the way up until xinput where the pressure value just disappeared. It turns out that it’s a known issue in xserver-xorg-input-evdev as reported here.

So following a suggestion from the poster of the bug report I decided to try downgrading evdev to the previously working version and that seems to bring back the pressure sensitivity.

To remove the current (buggy) version of evdev used synaptic but you could just as easily use apt: sudo apt-get remove xserver-xorg-input-evdev

Getting the older version of evdev is a little more complicated, since it’s not a current version any more it’s no longer held in the current (yakkety) repo so it needs to be downloaded as a .deb package from http://packages.ubuntu.com/xenial/xserver-xorg-input-evdev .

Just download the file you need for the architecture (uname -m to check) that you’re running. In my case (x86_64) I needed the amd64 build so got that.

To install we need to use dpkg via this command: sudo dpkg -i xserver-xorg-input-evdev_2.10.1-1ubuntu2_amd64.deb change the filename to whatever your download is. Hopefully after restarting pressure sensitivity should be working again.

Finally, to stop the system updating to the newer version we need to lock the package. To do this I used Synaptic, find and highlight xserver-xorg-input-evdev and use the [Package] menu to [Lock Version].