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From: Jiri Kosina <jikos@kernel.org>
To: Frank Yang <puilp0502@gmail.com>
Cc: linux-input@vger.kernel.org,
	Benjamin Tissoires <benjamin.tissoires@redhat.com>
Subject: Re: [PATCH] HID: Support Varmilo Keyboards' media hotkeys
Date: Mon, 17 Aug 2020 12:03:26 +0200 (CEST)	[thread overview]
Message-ID: <nycvar.YFH.7.76.2008171202130.27422@cbobk.fhfr.pm> (raw)
In-Reply-To: <20200729135341.16799-1-puilp0502@gmail.com>

On Wed, 29 Jul 2020, Frank Yang wrote:

> The Varmilo VA104M Keyboard (04b4:07b1, reported as Varmilo Z104M)
> exposes media control hotkeys as a USB HID consumer control device,
> but these keys do not work in the current (5.8-rc1) kernel due to
> the incorrect HID report descriptor. Fix the problem by modifying
> the internal HID report descriptor.
> 
> More specifically, the keyboard report descriptor specifies the
> logical boundary as 572~10754 (0x023c ~ 0x2a02) while the usage
> boundary is specified as 0~10754 (0x00 ~ 0x2a02). This results in an
> incorrect interpretation of input reports, causing inputs to be ignored.
> By setting the Logical Minimum to zero, we align the logical boundary
> with the Usage ID boundary.
> 
> Some notes:
> 
> * There seem to be multiple variants of the VA104M keyboard. This
>   patch specifically targets 04b4:07b1 variant.
> 
> * The device works out-of-the-box on Windows platform with the generic
>   consumer control device driver (hidserv.inf). This suggests that
>   Windows either ignores the Logical Minimum/Logical Maximum or
>   interprets the Usage ID assignment differently from the linux
>   implementation; Maybe there are other devices out there that only
>   works on Windows due to this problem?
> 
> Signed-off-by: Frank Yang <puilp0502@gmail.com>
> ---
>  drivers/hid/Kconfig       |  6 ++++
>  drivers/hid/Makefile      |  1 +
>  drivers/hid/hid-ids.h     |  2 ++
>  drivers/hid/hid-varmilo.c | 58 +++++++++++++++++++++++++++++++++++++++

Hi Frank,

thanks for the patch.

Given the fact that the device presents itself with CYPRESS VID (0x04b4, 
'officially' assigned to cypress), can we avoid creating extra driver, and 
rather extend hid-cypress.c with this quirk, please?

Thanks,

-- 
Jiri Kosina
SUSE Labs


  reply	other threads:[~2020-08-17 10:03 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-29 13:53 [PATCH] HID: Support Varmilo Keyboards' media hotkeys Frank Yang
2020-08-17 10:03 ` Jiri Kosina [this message]
2020-08-20 18:23   ` Frank Yang
2020-08-20 18:16 ` [PATCH v2] " Frank Yang
2020-10-23 11:25   ` Jiri Kosina
  -- strict thread matches above, loose matches on Subject: below --
2020-07-20 20:09 [PATCH] " Frank Yang
2020-07-20 20:24 ` Frank Yang

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