Re: [DIGImend-devel] [DIGImend-users] Patching the hid-uclogic driver for UC-Logic tablet TWHA60 v3

[Martin S. <mcs...@gm...>]

Hi Nick,

[Note that I've moved the thread from digimend-users to digimend-devel]

Thank you for the pointer to the development version.  Unfortunately
the development driver crashed when I loaded it on my system. I've
attached the corresponding traceback from dmesg.

What I did to try the driver was as follows: I removed everything from
/lib/modules/`uname -r`/extra/, to ensure that I didn't end up running
my version of the hid_uclogic driver by mistake. I then used rmmod to
unload both usbhid and hid_uclogic. I then downloaded
https://github.com/DIGImend/digimend-kernel-drivers/archive/master.zip
and unzipped it. I ran make on this, and then sudo make install, then
verified that the new drivers appeared under /lib/modules/`uname
-r`/extra/. Finally I ran modprobe on usbhid to load it and the new
hid_uclogic driver.  When the tablet didn't appear to be recognized, I
checked dmesg and found the traceback that's attached to this message.

After that I had to reboot, because rmmod hung when I tried to unload
the crashed driver.

I'll be happy to run any diagnostics that you suggest.

Thanks,

Martin

On Sun, May 31, 2015 at 4:12 AM, Nikolai Kondrashov <sp...@gm...> wrote:
> Hi Martin,
>
>
> On 05/29/2015 04:32 AM, Martin Shepherd wrote:
>>
>> On the digimend tablets web page UC-Logic Tablet TWHA60 v3 is listed as
>> unsupported. I have this tablet, and I've just managed to get its stylus
>> working by making a very small change to hid-uclogic.c.  With this change,
>> basic positioning, clicking the tip, and pressure sensitivity all appear
>> to
>> work correctly (at least in inkscape).
>>
>> The report descriptor for interface 0 has a different size in this tablet
>> than previous versions, so the code that substitutes a fixed descriptor,
>> based on this size, does nothing. To resolve this, I added an extra if()
>> to
>> check for the new descriptor size, and substituted a slightly different
>> fixed descriptor. The only changes needed in the fixed descriptor, were to
>> the logical maximums for X and Y, which should both be 2047, instead of
>> the
>> previous values of 39999 and 24999.
>>
>> I have placed the diff between the 3.13.0-53-generic (Ubuntu) version of
>> the
>> hid-uclogic.c file, and the fixed version, in the attached text file. I
>> hope
>> that this is the correct place to post this.
>
>
> Contributions are welcome anywhere, although
> DIG...@li... would be a bit more appropriate.
>
> We actually have this tablet supported in the development version of our
> out-of-tree driver:
>
> https://github.com/DIGImend/digimend-kernel-drivers/archive/master.zip
>
> Here's the GitHub page for it:
> https://github.com/DIGImend/digimend-kernel-drivers
>
> I need to update the website though.
>
> Nick