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From:   Benjamin Tissoires <benjamin.tissoires@redhat.com>
Date:   Fri, 11 Oct 2019 16:55:51 +0200
Message-ID: <CAO-hwJJ8tp4Rqte-umv9e=S5evR5oJTErsNR0Wk-z8wcbtR0wg@mail.gmail.com>
Subject: Re: [PATCH 3/3] HID: logitech-hidpp: add G920 device validation quirk
To:     Andrey Smirnov <andrew.smirnov@gmail.com>
Cc:     "open list:HID CORE LAYER" <linux-input@vger.kernel.org>,
        Sam Bazely <sambazley@fastmail.com>,
        Jiri Kosina <jikos@kernel.org>,
        Henrik Rydberg <rydberg@bitmath.org>,
        "Pierre-Loup A . Griffais" <pgriffais@valvesoftware.com>,
        Austin Palmer <austinp@valvesoftware.com>,
        lkml <linux-kernel@vger.kernel.org>,
        "3.8+" <stable@vger.kernel.org>
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On Mon, Oct 7, 2019 at 7:13 AM Andrey Smirnov <andrew.smirnov@gmail.com> wr=
ote:
>
> G920 device only advertises REPORT_ID_HIDPP_LONG and
> REPORT_ID_HIDPP_VERY_LONG in its HID report descriptor, so querying
> for REPORT_ID_HIDPP_SHORT with optional=3Dfalse will always fail and
> prevent G920 to be recognized as a valid HID++ device.
>
> Modify hidpp_validate_device() to check only REPORT_ID_HIDPP_LONG with
> optional=3Dfalse on G920 to fix this.
>
> Fixes: fe3ee1ec007b ("HID: logitech-hidpp: allow non HID++ devices to be =
handled by this module")
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=3D204191
> Reported-by: Sam Bazely <sambazley@fastmail.com>
> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
> Cc: Jiri Kosina <jikos@kernel.org>
> Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> Cc: Henrik Rydberg <rydberg@bitmath.org>
> Cc: Sam Bazely <sambazley@fastmail.com>
> Cc: Pierre-Loup A. Griffais <pgriffais@valvesoftware.com>
> Cc: Austin Palmer <austinp@valvesoftware.com>
> Cc: linux-input@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Cc: stable@vger.kernel.org
> ---
>  drivers/hid/hid-logitech-hidpp.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-=
hidpp.c
> index cadf36d6c6f3..f415bf398e17 100644
> --- a/drivers/hid/hid-logitech-hidpp.c
> +++ b/drivers/hid/hid-logitech-hidpp.c
> @@ -3511,6 +3511,12 @@ static bool hidpp_validate_report(struct hid_devic=
e *hdev, int id,
>
>  static bool hidpp_validate_device(struct hid_device *hdev)
>  {
> +       struct hidpp_device *hidpp =3D hid_get_drvdata(hdev);
> +
> +       if (hidpp->quirks & HIDPP_QUIRK_CLASS_G920)
> +               return hidpp_validate_report(hdev, REPORT_ID_HIDPP_LONG,
> +                                            HIDPP_REPORT_SHORT_LENGTH, f=
alse);
> +

with https://patchwork.kernel.org/patch/11184749/ we also have a need
for such a trick for BLE mice.

I wonder if we should not have a more common way of validating the devices

This can probably be handled later, as your patch fixes the current devices=
.

Cheers,
Benjamin

>         return hidpp_validate_report(hdev, REPORT_ID_HIDPP_SHORT,
>                                      HIDPP_REPORT_SHORT_LENGTH, false) &&
>                hidpp_validate_report(hdev, REPORT_ID_HIDPP_LONG,
> --
> 2.21.0
>