linux-kernel - Re: Status on hid xppen patch

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Message-ID: <ebb6d627-4974-beed-1dc6-60634ab2f034@gmail.com>
Date:   Fri, 13 May 2022 19:22:49 +0200
From:   Stefan Berzl <stefanberzl@...il.com>
To:     José Expósito <jose.exposito89@...il.com>
Cc:     jikos@...nel.org, benjamin.tissoires@...hat.com, spbnick@...il.com,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: Status on hid xppen patch

Hello José,

> The tablets are the Deco Mini 4 and the Deco L, both of them are UGEE
> tablets. I already had a UGEE Parblo A610 Pro tablet and after having a
> look to the Windows driver traffic, I found out that after sending a
> chunk of magic data to enable the tablet, it requests a string
> descriptor ("uclogic_params_get_str_desc" can be used here) and the
> tablets respond with their parameters.
> 
> The information is encoded, in bytes, as:
> 
>  02 + 03 - UCLOGIC_RDESC_PEN_PH_ID_X_LM
>  04 + 05 - UCLOGIC_RDESC_PEN_PH_ID_Y_LM
>  06      - Number of buttons
>  07      - Dial present or not
>  08 + 09 - UCLOGIC_RDESC_PEN_PH_ID_PRESSURE_LM
>  10 + 11 - Resolution
> 
> Bytes 12 and 13 are present but set to 0, probably indicating my
> tablets are lacking some feature.
> 
> Could you confirm that your tablet returns similar information, please?

yes, you can haz string descriptor:
0e 03 0b 8b cb 56 08 00 ff 1f d8 13

Byte 12 are 13 are set and zero, as in your case.

> In case you want to have a look to the implementation, I'm working on
> this branch:
> https://github.com/JoseExposito/linux/commits/patch-xppen-deco-l
> 
> I had to introduce new functionalities to the templating system of the
> driver, that's the reason for the KUnit tests.
> The last patch is work in progress (hopefully I'll have time to finish
> it this weekend), only the HID descriptors are missing.

I hope you make it, but otherwise you can always use mine, as it's quite
the same as yours. Only the logical minimum and maximum are -60 and 60.

> I'll cc you when in the patchset so you can add your IDs :)

Is that all you want me to do?

Kind regards,
Stefan Berzl