Wrong number of buttons for Wacom Bamboo Ink CS323A/G0-BX

[martinprejsa]

I own a Wacom Bamboo Ink and and a HP Elitebook x360 830 G8. This setup worked perfectly until i updated my Plasma DE to version 6.3.0. After some investigation i realized that this update switched to using libwacom to retrieve the amount of buttons on the pen. Which made one of the buttons unconfigurable.

The pen I'm using is Wacom Bamboo Ink CS323A/G0-BX which has two buttons, but libwacom only reports a single button. The tablet my laptop is using is ISDv4 496c.

I hope this issue gets resolved quickly. Thanks in advance.

[whot]

Run the libwacom-show-stylus tool please (show-stylus.py in the repo, iirc you can run it directly), we'll need the tool id of your pen. But afaict we already have that entry:

[0x271]
# Wacom  ; VID_NONE     | 0x0000 | BAT_SWAP ("Wacom Bamboo Ink" / CS323A)
Name=Bamboo Ink
Group=isdv4-aes
Buttons=1
EraserType=Button
Axes=Pressure
Type=Mobile

And it looks like this one has an eraser button which cannot be configured anyway. Did this button actually send button events before?

[martinprejsa]

That's interesting, i didn't know that the eraser button was not supposed to be configurable.
Before the Plasma update, both of the buttons were set to Application-defined behavior. And it worked well.

In fact both of the buttons still work in Krita alright (one eraser, and the second button is a middle mouse click for some reason), just checked. I'm having problems with Rnote which doesn't accept input from the eraser button.

Does this mean this is a application specific issue?

$ python show-stylus.py
Using "Wacom HID 496C Pen": /dev/input/event7
Using stylus file(s): /usr/share/libwacom/libwacom.stylus
Tool id 0x271 serial 0x262acd in-proximity: False 

[whot]

That's interesting, i didn't know that the eraser button was not supposed to be configurable.

The eraser button literally emulates the pen going out of proximity and coming back in with the eraser end - and that's been a MS requirement for maybe 10 or 15 years now. Which means in userspace we can only work around it through heuristics but those tend to be complicated given the way the stack works atm. udev-hid-bpf has a few BPFs that convert the button into a normal button but that is device-specific. And that would allow you to change the eraser button into a true button, but KDE (and anything else) would still only show one configurable button then since it cannot know the device was modified.

Before the Plasma update, both of the buttons were set to Application-defined behavior. And it worked well.

Could you actually configure them as something other than the eraser?

anyway, libwacom is a static set of data files describing the physical device, afaict the data we provide is correct for this pen so there's nothing we can (or need to) do here. Not accepting the eraser input is a bug in Rnote and not showing the eraser button as configurable is unfortunately correct given that it cannot be configured.

[github-actions]

Hi, there. I'm a bot and have been asked to have a look at this.

libwacom is a bunch of text files with a C API, and the information in those text files
is static fixed information that we cannot get from the device (e.g. the model name or which
button will produce which event code). It does not affect functionality directly, if the
tablet does not work this is either an issue with the kernel drivers, xf86-input-wacom
(if using X) or libinput/the desktop environment (if using Wayland). Please file the
issue with the component that most likely applies.

See also https://github.com/linuxwacom/libwacom/wiki/Troubleshooting
See also https://github.com/linuxwacom/libwacom/wiki/Adding-a-new-device

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