Update gaomon-s620.tablet

[FlashNoob98]

I updated the tablet firmware (through the windows tool) and now it displays as

ID 256c:006f GAOMON Gaomon Tablet 

with lsusb, but the device is still not working on GNOME

[FlashNoob98]

The device is now shown as S620 in Gnome settings but no input is given.
I got this error from libinput:

event4  - GAOMON Gaomon Tablet Pen: libinput bug: missing tablet capabilities: resolution. Ignoring this device

Otherwise, I solved the problem installing the driver from their website

cat /lib/udev/rules.d/20-gaomon.rules 
# udev rules for GaoMonTablet supported devices
# This file is generated by GaoMonTablet driver, do not edit

KERNEL=="uhid",MODE:="0666",OPTIONS+="static_node=uhid"
KERNEL=="uinput",MODE:="0666",OPTIONS+="static_node=uinput"
SUBSYSTEMS=="usb",ATTRS{idVendor}=="256c",MODE:="0666"
SUBSYSTEM=="input", KERNEL=="event*",ATTRS{name}=="HUION 256C PEN STYLUS",MODE:="0644"

[whot]

This means the kernel driver needs updating because the resolution may now be exported through some other bitfield that isn't yet parsed. In theory we could add an entry to 60-evdev.hwdb to hardcode the resolution but we cannot do this for the Gaomon devices because they all share the same USB ID so we'd overwrite it for other devices too.

On that note: can you please run the sysinfo script from https://github.com/linuxwacom/wacom-hid-descriptors and attach the output in an issue there (see the readme in that repo). Yesterday I looked for an S620 output and couldn't find any which prevented me to work on #610.

And second note: @FlashNoob98, meet @TacticalCode (and vice versa :). You two have an S620 and an M106K which re-use each other's USB ID, we're trying to figure out how to differ between the devices in userspace and it'd be great if you can help each other. See #609 and #610.

[TacticalCode]

@whot My USB ID for the M106K is 256c:006d, but I also haven't ever updated the firmware.

There also is a Gaomon "1080Pro" (reporting as "1060Pro") sysinfo with ID 256c:0064: linuxwacom/wacom-hid-descriptors#344
So I'm starting to think that maybe the S620 just had the wrong ID, or the manufacturer fixed the identical IDs with newer firmware?

@FlashNoob98 can you plug in your pad and run libwacom-list-local-devices?
If it's not listed there, you just need to override the current DeviceMatch string in the tablet definition:

sudo -i
mkdir /etc/libwacom
sed -e 's/256c:006d/256c:006f/g' /usr/share/libwacom/gaomon-s620.tablet > /etc/libwacom/gaomon-s620.tablet
libwacom-update-db

Re-attach the pad and run libwacom-list-local-devices, it should now show up and be configurable in gnome-settings.

Also, just for clarity, S620 is what you bought and not just what gnome-settings reports, right? Because right now most/all Gaomon pads are shown as "S620" in gnome-settings. That sysinfo would be really nice to have.