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Improving Linux support for graphics tablets.

Collecting tablet diagnostics

You can follow these steps to collect information which can help make a driver for your tablet.

Note that the DIGImend project doesn’t have the capacity to process all diagnostics and make drivers for all possible tablets, so we cannot promise that any drivers will be made for the tablet in question.

All the steps need to be executed in a terminal with the tablet plugged in. You could use either a text mode console or a terminal emulator running under X. However, please don’t rely on your tablet to control the terminal, as some steps will temporarily detach it from the kernel driver, which will stop your terminal from receiving the input.

You will need “lsusb” and “usbhid-dump” utilities which are both included into “usbutils” package, available in most distributions.

You will also need the “uclogic-probe” utility, which is a part of the “uclogic-tools” package.

Identify original model

Use lsusb to find the tablet’s USB vendor and product IDs (USB VID/PID). Run “lsusb” and find the line containing your tablet model or manufacturer’s name in the output. The VID/PID pair will be displayed next to “ID” as two hexadecimal numbers separated by a colon.


$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 004: ID 2232:1001
Bus 003 Device 002: ID 046d:c52b Logitech, Inc. Unifying Receiver
Bus 003 Device 003: ID 0a5c:219c Broadcom Corp.
Bus 005 Device 002: ID 172f:0501 Waltop International Corp. Media Tablet 10.6"

“172f:0501” above is the Waltop Media Tablet 10.6” USB VID and PID.

If you can’t identify your tablet just by looking at vendor/product names, you could unplug it, run lsusb, plug it back, run lsusb again and notice which line has appeared - it will represent your tablet.

For convenience executing the following steps, you could put the found VID/PID pair in a shell variable, like this:

$ T=172f:0501

The following examples will refer to this shell variable as “$T” and will assume it contains the tablet VID/PID pair. So, if you assign it, you could just copy-paste and execute the commands from the examples in your terminal.

Retrieve USB descriptors

Retrieve USB device, configuration, interface and endpoint descriptors, using lsusb. Run “sudo lsusb -v -d VID:PID” and attach the output to the diagnostics message.


$ sudo lsusb -v -d $T > descriptors.txt

The above stores the lsusb output in “descriptors.txt” file.

Retrieve USB HID report descriptor(s) using usbhid-dump. Run “sudo usbhid-dump -ed -m VID:PID” and attach the output to the diagnostics message.


$ sudo usbhid-dump -ed -m $T > hid_report_descriptors.txt

The above stores the usbhid-dump output in “hid_report_descriptors.txt” file.

Attempt retrieving UC-Logic parameters

Many tablets on the market today (e.g. Huion, Ugee, and XP-Pen) are based on UC-Logic hardware, which uses a certain protocol for exposing tablet parameters. Having that information is necessary to implement support for such tablets in the DIGImend drivers.

You can use the “uclogic-probe” tool from the “uclogic-tools” package to try to retrieve those parameters. There is no harm in using it on tablets which are not based on UC-Logic hardware. OTOH it is important to run “uclogic-probe” before proceeding to collecting input samples, as they can change as a result of running it.

First, determine the USB bus your tablet is connected to and the device number it was assigned:

$ lsusb -d $T
Bus 001 Device 006: ID 256c:006e  

The above output shows that the tablet is attached to bus 1 and has device number 6.

Then, run “uclogic-probe” supplying the bus and device numbers as the arguments, and saving the output to file “probe.txt”:

$ sudo uclogic-probe 1 6 | tee probe.txt
S C8 13 03 A8 AC 00 D0 6B 00 FF 1F D8 13 03 08 00 00 04 00 40
S C9 24 03 48 00 55 00 49 00 4F 00 4E 00 5F 00 54 00 31 00 37 00 32 00 5F 00 31 00 38 00 30 00 36 00 30 00 34 00
S CA 46 03 48 00 55 00 49 00 4F 00 4E 00 20 00 41 00 6E 00 69 00 6D 00 61 00 74 00 69 00 6F 00 6E 00 20 00 54 00 65 00 63 00 68 00 6E 00 6F 00 6C 00 6F 00 67 00 79 00 20 00 43 00 6F 00 2E 00 2C 00 6C 00 74 00 64 00

NOTE: Instead of using “1” and “6” as shown above, substitute the numbers you found in the previous step.

Collect raw input samples

Raw input samples could be collected either with usbhid-dump or with a USB traffic sniffer, such as Wireshark or tcpdump. In most cases ubshid-dump is sufficient.

There are several input samples to be collected. Please put them into separate attachments, if possible. To collect an input sample with usbhid-dump, execute “sudo usbhid-dump -es -m VID:PID”. It is best to redirect sample output to a file, because there is often quite a lot of it.


$ sudo usbhid-dump -es -m $T | tee frame_wheel_srolling.txt
Starting dumping interrupt transfer stream
with 1 minute timeout.

005:002:000:STREAM             1331485997.649152
 01 00 00 00 FF 00 00 00

005:002:000:STREAM             1331485999.213131
 01 00 00 00 01 00 00 00

005:002:000:STREAM             1331486014.777136
 01 00 00 00 00 FF 00 00

005:002:000:STREAM             1331486016.477138
 01 00 00 00 00 01 00 00


Here, the displayed stream output will also be stored in “frame_wheel_srolling.txt” file.

Please follow the (applicable) steps below to collect all the sample types. Each step has an example command you could copy-paste into your terminal to have the output stored in separate and appropriately-named files. When capturing each sample type, it is better to repeat the described input 3 to 5 times for better precision.


All graphics tablets have a pen, so these samples are required.


Make four strokes with the pen, starting from inside the tablet working area, slowly moving outside and crossing each border in the following (clockwise) order: top, right, bottom, left.

$ sudo usbhid-dump -es -m $T | tee pen_coords.txt

Tilt angles

If you’re sure your tablet doesn’t support pen tilt angle reporting, please skip this step. Otherwise, please collect a sample. Most inexpensive tablets don’t support it, though.

Put the pen vertically, tip touching the center of the working area, and slowly tilt the opposing end towards each working area border in turn, as far as the pen shape allows, without lifting the pen tip, then tilt it back. It is OK if the pen tip is lifted during tilting, it is just unnecessary to tilt further than that. Please tilt towards the borders in the following (clockwise) order: top, right, bottom, left.

$ sudo usbhid-dump -es -m $T | tee pen_tilt.txt


Hold your pen as you do for drawing and press its tip on the working tablet surface with the strength appropriate for the full pressure - press it until it stops sliding into the pen and then press a little more. Please don’t press hard enough to break the tip.

$ sudo usbhid-dump -es -m $T | tee pen_pressure.txt


Bring the pen tip close to the tablet surface (within, say, 5 mm / 0.2 inches), but not touching it or anything else. Then, holding the pen with one hand, press the pen side buttons with the other, first - the lower button, then the upper. It doesn’t matter if the pen tip touches anything in between presses, it is only important it doesn’t touch anything at the same time as pressing the buttons.

$ sudo usbhid-dump -es -m $T | tee pen_buttons.txt

Frame controls

If your tablet doesn’t have additional controls on the frame, such as buttons or dials, please skip these steps.


When generic tablets have dials, they often have buttons, which control their function. Please capture input samples for every dial function mode. In each mode, please do several rotations of the dials, first clockwise, then counter-clockwise.

There are usually two dials on either side of the tablet, which produce the same input and are intended for equally convenient right/left-handed use, so there is no need to rotate both of them.

Touch-based sensor dials could be acting as directional buttons in some modes. In such cases, please press every direction in this (clockwise) order: top, right, bottom, left.

$ sudo usbhid-dump -es -m $T | tee frame_dials.txt


If your tablet has no buttons on the frame, aside from those controlling dials’ input mode, please skip this step.

Please press every button on the frame, in left-to-right, top-to-bottom order. If the order still wasn’t obvious, please describe it in the message.

If there are two identical (mirrored) sets of buttons on either side of the working area, please press first the buttons on the left, then those on the right. Although these buttons are intended to be equally used by left and right hand, they may produce different key codes.

$ sudo usbhid-dump -es -m $T | tee frame_buttons.txt


If your tablet didn’t have a mouse bundled, please skip these steps.


Place the mouse within the working area and move it outside, over each border in turn, in this (clockwise) order: top, right, bottom, left. It may be more convenient to hold the mouse by its sides so it is easier to lift a little over the bezel edge.

$ sudo usbhid-dump -es -m $T | tee mouse_coords.txt


Place the mouse within the working area and then click each button in turn in this order: left, right, middle.

$ sudo usbhid-dump -es -m $T | tee mouse_buttons.txt


Some older tablet mice have rocking wheel, which only rocks (clicks) in two directions, while newer models have traditional, fully rotating wheels.

Place the mouse within the working area and rotate (rock) the wheel, first away from you, then towards you.

$ sudo usbhid-dump -es -m $T | tee mouse_wheel.txt

Post the results

Once you’re done, attach the resulting files to the relevant digimend-kernel-drivers issue on GitHub, or create a new one. Make sure to mention the tablet manufacturer and model name, and add a link to the product page, e.g. on the website you bought it from, or on manufacturer’s website.