Re: [PATCH] HID: elecom: Add support for ELECOM M-XT4DRBK (018E)

[Jiri Kosina]

On Mon, 7 Sep 2026, Berke Durak wrote:

> The 2025 revision of the left-handed EX-G wireless trackball
> (M-XT4DRBK-G) reports USB ID 056e:018e instead of 056e:00fd. Its report
> descriptor declares an 8-bit button field (Report Count 8) but only five
> usages (Usage Maximum 5), so the sixth (Fn) button ends up as a
> duplicate of button 5 and is unusable.
> 
> The report descriptor has the same layout as the M-XT3DRBK 018C
> (button usage maximum at offset 16, button report count at 22, button
> report size at 24, padding report size at 30), so reuse that fixup.
> 
> Rename the existing M_XT4DRBK define to M_XT4DRBK_00FD to match the
> convention used for the other EX-G revisions.
> 
> Tested on a Raspberry Pi 5 with the same fixup in an         
> out-of-tree module on 6.12 (6.12.96+rpt-rpi-2712);
> all six buttons are reported after the fix, and they
> work (tested with xev as well).
> 
> Report descriptor as sent by the device, pre-fix (056e:018e,
> 215 bytes):
> 
>  05 01 09 02 A1 01 09 01 A1 00 85 01 05 09 19 01
>  29 05 15 00 25 01 95 08 75 01 81 02 95 01 75 00
>  81 01 05 01 09 30 09 31 16 00 80 26 FF 7F 75 10
>  95 02 81 06 C0 A1 00 05 01 09 38 15 81 25 7F 75
>  08 95 01 81 06 C0 A1 00 05 0C 0A 38 02 95 01 75
>  08 15 81 25 7F 81 06 C0 C0 06 01 FF 09 00 A1 01
>  85 02 09 00 15 00 26 FF 00 75 08 95 07 81 02 C0
>  05 0C 09 01 A1 01 85 05 15 00 26 3C 02 19 00 2A
>  3C 02 75 10 95 01 81 00 C0 05 01 09 80 A1 01 85
>  03 19 81 29 83 15 00 25 01 95 03 75 01 81 02 95
>  01 75 05 81 01 C0 06 BC FF 09 88 A1 01 85 04 95
>  01 75 08 15 00 26 FF 00 19 00 2A FF 00 81 00 C0
>  06 02 FF 09 02 A1 01 85 06 09 02 15 00 26 FF 00
>  75 08 95 07 B1 02 C0
> 
> Assisted-by: LLM
> Signed-off-by: Berke Durak <berke.durak@xxxxxxxxx>

Applied, thanks.

-- 
Jiri Kosina
SUSE Labs