On Nov 07 2017 or thereabouts, Hans de Goede wrote:
> This commit fixes 2 different issues with buttons on touchpads in one go:
>
> 1) Devices in "single finger hybrid mode" will send one report per finger,
> on some devices only the first report of such a multi-packet frame will
> contain a value for BTN_LEFT, in subsequent reports (if multiple fingers
> are down) the value is always 0, causing hid-mt to report BTN_LEFT going
> 1 - 0 - 1 - 0 when pressing a clickpad and putting down a second finger.
> This happens for example on USB 0603:0002 mt touchpads.
>
> 2) According to the Win8 Precision Touchpad spec, inside the HID_UP_BUTTON
> usage-page usage 1 is for a clickpad getting clicked, 2 for an external
> left button and 3 for an external right button. Since Linux uses
> BTN_LEFT for a clickpad being clicked we end up mapping both usage 1
> and 2 to BTN_LEFT and if a single report contains both then we ended
> up always reporting the value of both in a single SYN, e.g. :
> BTN_LEFT 1, BTN_LEFT 0, SYN. This happens for example with Hantick
> HTT5288 i2c mt touchpads.
>
> This commit fixes both issues by not immediately reporting buttons when
> we parse the report, but instead storing the values of button fields and
> reporting the result from mt_sync_frame() when we've a complete frame.
>
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> ---
> Changes in v2:
> -Rewrite of v1 of "HID: multitouch: Fix BTN_LEFT 0-1-0-1 events on Novatek
> mt touchpad" to kill two birds with one stone
>
> Changes in v3:
> -Delay reporting for all buttons not just for BTN_LEFT
> ---
> drivers/hid/hid-multitouch.c | 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
>
> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
> index 5d3904d0e89d..bfbfa04d023a 100644
> --- a/drivers/hid/hid-multitouch.c
> +++ b/drivers/hid/hid-multitouch.c
> @@ -83,6 +83,8 @@ MODULE_LICENSE("GPL");
> #define MT_IO_FLAGS_ACTIVE_SLOTS 1
> #define MT_IO_FLAGS_PENDING_SLOTS 2
>
> +#define BTN_COUNT (BTN_JOYSTICK - BTN_MOUSE)
> +
> struct mt_slot {
> __s32 x, y, cx, cy, p, w, h;
> __s32 contactid; /* the device ContactID assigned to this slot */
> @@ -120,6 +122,7 @@ struct mt_device {
> int scantime_index; /* scantime field index in the report */
> int scantime_val_index; /* scantime value index in the field */
> int prev_scantime; /* scantime reported in the previous packet */
> + int buttons_state; /* buttons state */
> unsigned last_slot_field; /* the last field of a slot */
> unsigned mt_report_id; /* the report ID of the multitouch device */
> unsigned long initial_quirks; /* initial quirks state */
> @@ -728,9 +731,17 @@ static void mt_complete_slot(struct mt_device *td, struct input_dev *input)
> */
> static void mt_sync_frame(struct mt_device *td, struct input_dev *input)
> {
> + int i;
> +
> + /* For non Win8 devices buttons_state = 0, so this is a no-op */
> + for (i = 0; i < BTN_COUNT; i++)
> + input_event(input, EV_KEY, BTN_MOUSE + i,
> + (td->buttons_state >> i) & 1);
> +
> input_mt_sync_frame(input);
> input_sync(input);
> td->num_received = 0;
> + td->buttons_state = 0;
> if (test_bit(MT_IO_FLAGS_ACTIVE_SLOTS, &td->mt_io_flags))
> set_bit(MT_IO_FLAGS_PENDING_SLOTS, &td->mt_io_flags);
> else
> @@ -752,6 +763,7 @@ static void mt_process_mt_event(struct hid_device *hid, struct hid_field *field,
> struct hid_usage *usage, __s32 value)
> {
> struct mt_device *td = hid_get_drvdata(hid);
> + __s32 cls = td->mtclass.name;
> __s32 quirks = td->mtclass.quirks;
> struct input_dev *input = field->hidinput->input;
>
> @@ -805,6 +817,19 @@ static void mt_process_mt_event(struct hid_device *hid, struct hid_field *field,
> break;
>
> default:
> + /*
> + * For Win8 PTP touchpads the button state should be
> + * reported once we've a complete frame, so we store
> + * the state here and report it in mt_sync_frame().
> + */
> + if ((cls == MT_CLS_WIN_8 || cls == MT_CLS_WIN_8_DUAL) &&
> + usage->type == EV_KEY && usage->code >= BTN_MOUSE &&
> + usage->code < BTN_JOYSTICK) {
> + int btn = usage->code - BTN_MOUSE;
> + td->buttons_state |= (!!value) << btn;
> + return;
> + }
> +
I think there is no point in storing the data and only matching for
BTN_* events here.
How about you simply extend the test below in case the device is
following Win8 protocol and that we have a scantime matching the one
stored in td->prev_scantime?
This way we would only deal with non-multitouch events if they are
reported in the first frame, and ignore all of the others.
I do not believe there are other events than BTN_* that are handled
here, so we should be safe.
Cheers,
Benjamin
> if (usage->type)
> input_event(input, usage->type, usage->code,
> value);
> --
> 2.14.3
>
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