Troubleshooting VEIKK Drawing Tablet

User Support General
1

I’m having trouble getting A VEIKK drawing tablet to work.
I installed the driver in dom0. The tablet shows in USB devices, yet the driver app in Dom0 doesn’t see a connected device.

I get the message when plugging in the tablet: “Denied; qubes.inputtablet from sys-usb.”

Yet some of the tablet inputs work. Most don’t.

I can imagine Dom0 is blocking these inputs.

How would I whitelist the tablet, so the inputs are allowed?

2

Is there a chance that the driver doesn’t declare the device as a tablet?

What does dmesg say when you connect it?

EDIT: Disregard my advice on this one. I misread your post. It’s likely that it’s a qubes-rpc issue. My bad…

3

Have you set the policy in /etc/qubes-rpc/policy/qubes.InputTablet ?
By default it’s a deny.

4

I tried:
sys-usb dom0 allow,user=root
sys-usb dom0 allow

Neither of those configs allowed the driver to connect to the device in dom0.

I was able to install the driver in a qube, and then attach the device to the qube. The driver sees it, but some of the inputs won’t work.

The input I can’t seem to get to work is the mouse arrow doesn’t track to the pen.

Is there another flag to set to “allow” to get the mouse input on the tablet to work?

Is there another flag to set to get dom0 to recognize the device?

5

Is there any sort of denied notification in dom0?

I’ve had USB sound cards identify themselves as keyboards (apparently that’s how the sound card firmware chose to communicate the play/pause and volume buttons on TRRS headphone jacks).

I’ve also had gamepad declare themselves as a keyboard and mouse and a gamepad simultaneously.

Is there any chance that it might be declaring itself to be a mouse?

6

It was giving me a Tablet denied notification. But changing the qubes.inputTablet setting changed that.
I can imagine it was identifying itself as a tablet from that notifcation.

Interestingly enough, the right click input works on the mouse aspect of the Tablet. But the mouse pointer does not follow the stylus.

If I could get it to recognize as a mouse, maybe it would work?

7

That’s interesting, because you’re not getting any kind of denied notifications about any mouse input.

I think it already is recognised as a mouse input as well as a tablet input.

When you plug it in, how many confirmation dialogs do you get? Just the one, or two?

8

Just one. (The name of the Tablet.)

The mouse inputs seems to be working. But, the actual mouse cursor doesn’t track to the input. So while something seems to be happening moving the windows in the background, I’m not getting the feedback from the cursor to know where the mouse is on the screen.

9

So:

Action Expected Behaviour Actual Behaviour
Hover stylus above tablet Cursor moves to same point on screen Cursor does not move
Touch tablet with stylus Left-click (I’m assuming?) Left-click
Touch tablet with stylus and move tip around tablet Held down left-click Held down left-click
Press button 1 on stylus (Fill me in) (Fill me in)
Press button 2 on stylus (Fill me in) (Fill me in)

Is this correct?

10

Yes. The #1 button on the stylus is the left mouse click. #2 button does nothing.

I’ve set the permissions such that when the Veikk is plugged in Qubes prompts to allow for both tablet and mouse. Target: Dom0 is the only option it allows.

Interestingly enough, deleting sys-usb, and the Veikk works as expected. Re-installing sys-usb, and it doesn’t work.

I absolutely have to have this device working for my work. Is there anyway to disable all sys-usb inputs filtering for the Veikk tablet?

11

Is it possible to whitelist the Veikk device in the /etc/default/grub settings, yet still be able to connect it to a qube thru sys-usb?

12

If you have more than one USB controller, you could attach a controller to a hvm or dom0 and use that for the tablet.

13

Devices shows only one USB controller.
I know that without sys-usb installed, the device works.
Other than:

/etc/qubes-rpc/policy/qubes.InputKeyboard
/etc/qubes-rpc/policy/qubes.InputMouse
/etc/qubes-rpc/policy/qubes.USB

…where/how might sys-usb be configured to block the tablet inputs?

14

Then the possible causes are:

  • sys-usb doesn’t have the correct firmware
    - Unlikely, as there are kernel modules still a possibility
  • sys-usb isn’t passing through enough of the device to make the AppVM recognise it as a Veikk tablet
    - Possible. There are quite a few USB devices that don’t work as expected when passed through, particularly if they require direct hardware access (an EEPROM flasher or TTY serial cables are good examples that sometimes don’t behave as expected)
    - Also doubt it, as the devs are awesome.

Is there any possibility of getting the output of the following:

  • dmesg in dom0 when you plug it in without sys-usb open
  • dmesg in dom0 when you plug it in with sys-usb open and it passes through
  • dmesg in sys-usb when you plug it in
  • dmesg in the AppVM when you pass it through from sys-usb (If you pass it through to any AppVM)

That’ll tell us what each VM is seeing the device as.