linux-kernel - Re: [PATCH] hid: multitouch: new device class fix Lenovo X12 trackpad sticky

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Message-ID: <CAO-hwJJE_RAMXQA1kgpxVJWgGOsn64GxbN4fQVq8Dt2xepnYog@mail.gmail.com>
Date:   Thu, 21 Apr 2022 11:12:20 +0200
From:   Benjamin Tissoires <benjamin.tissoires@...hat.com>
To:     Tao Jin <tao-j@...look.com>
Cc:     linux-input@...r.kernel.org, Jiri Kosina <jikos@...nel.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] hid: multitouch: new device class fix Lenovo X12 trackpad sticky

On Mon, Apr 18, 2022 at 5:16 AM Tao Jin <tao-j@...look.com> wrote:
>
> The trackpad of the given device sends continuous report of pointers
> status as per wxn8 spec. However, the spec did not clarify when the
> fingers are lifted so fast that between the interval of two report
> frames fingers on pad reduced from >=2 to 0. The second last report
> contains >=2 fingers with tip state 1 and the last report contains only
> 1 finger with tip state 0. Although this can happen unfrequently, a
>   quick fix will be improve the consistency to 100%. A quick fix is to
> disable MT_QUIRK_ALWAYS_VALID and enable MT_QUIRK_NOT_SEEN_MEANS_UP.
> Since it always send reports when fingers on pad
> MT_QUIRK_STICKY_FINGERS is also not needed.

I would really like to see tests for this device added to hid-tools[0].

This would allow me to better understand the issue and also ensure we
are not regressing in the future.

Cheers,
Benjamin


[0] https://gitlab.freedesktop.org/libevdev/hid-tools

>
> In addition to this, I2C device 04CA:00B1 may also need similar class
> but with MT_QUIRK_FORCE_MULTI_INPUT disabled (but it does not harm to
>  enable it on non-multi-input device either). The respective owner has
> been notified and a patch may coming soon after test.
>
> Signed-off-by: Tao Jin <tao-j@...look.com>
> ---
>  drivers/hid/hid-multitouch.c | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
> index 0dece60..3ea57f3 100644
> --- a/drivers/hid/hid-multitouch.c
> +++ b/drivers/hid/hid-multitouch.c
> @@ -194,6 +194,7 @@ static void mt_post_parse(struct mt_device *td, struct mt_application *app);
>  #define MT_CLS_WIN_8_FORCE_MULTI_INPUT         0x0015
>  #define MT_CLS_WIN_8_DISABLE_WAKEUP            0x0016
>  #define MT_CLS_WIN_8_NO_STICKY_FINGERS         0x0017
> +#define MT_CLS_WIN_8_FORCE_MULTI_INPUT_NSMU    0x0018
>
>  /* vendor specific classes */
>  #define MT_CLS_3M                              0x0101
> @@ -286,6 +287,14 @@ static const struct mt_class mt_classes[] = {
>                         MT_QUIRK_WIN8_PTP_BUTTONS |
>                         MT_QUIRK_FORCE_MULTI_INPUT,
>                 .export_all_inputs = true },
> +       { .name = MT_CLS_WIN_8_FORCE_MULTI_INPUT_NSMU,
> +               .quirks = MT_QUIRK_IGNORE_DUPLICATES |
> +                       MT_QUIRK_HOVERING |
> +                       MT_QUIRK_CONTACT_CNT_ACCURATE |
> +                       MT_QUIRK_WIN8_PTP_BUTTONS |
> +                       MT_QUIRK_FORCE_MULTI_INPUT |
> +                       MT_QUIRK_NOT_SEEN_MEANS_UP,
> +               .export_all_inputs = true },
>         { .name = MT_CLS_WIN_8_DISABLE_WAKEUP,
>                 .quirks = MT_QUIRK_ALWAYS_VALID |
>                         MT_QUIRK_IGNORE_DUPLICATES |
> @@ -783,6 +792,7 @@ static int mt_touch_input_mapping(struct hid_device *hdev, struct hid_input *hi,
>                 case HID_DG_CONFIDENCE:
>                         if ((cls->name == MT_CLS_WIN_8 ||
>                              cls->name == MT_CLS_WIN_8_FORCE_MULTI_INPUT ||
> +                            cls->name == MT_CLS_WIN_8_FORCE_MULTI_INPUT_NSMU ||
>                              cls->name == MT_CLS_WIN_8_DISABLE_WAKEUP) &&
>                                 (field->application == HID_DG_TOUCHPAD ||
>                                  field->application == HID_DG_TOUCHSCREEN))
> @@ -2035,7 +2045,7 @@ static const struct hid_device_id mt_devices[] = {
>                            USB_DEVICE_ID_LENOVO_X1_TAB3) },
>
>         /* Lenovo X12 TAB Gen 1 */
> -       { .driver_data = MT_CLS_WIN_8_FORCE_MULTI_INPUT,
> +       { .driver_data = MT_CLS_WIN_8_FORCE_MULTI_INPUT_NSMU,
>                 HID_DEVICE(BUS_USB, HID_GROUP_MULTITOUCH_WIN_8,
>                            USB_VENDOR_ID_LENOVO,
>                            USB_DEVICE_ID_LENOVO_X12_TAB) },
> --
> 2.35.1
>