Re: [PATCH v2 20/20] HID: multitouch: Remove the redundant touch state

[Benjamin Tissoires]

Hi Henrik,

Thanks for the new version. I still didn't review in depth the patch
(it seemed to be fair).
However, I found out 2 bugs while testing it (related to the whole
series apparently):

- I don't know if it is my configuration or not, but I'm receiving at
each frame (between two EV_SYN) all ABS_MT_SLOT events, even when
there are not used.

- After a little bit a playing with some surfaces, I can confuse the
input_mt_assign_slot_by_id function: for the very same contact id, I
got up to four different slots.... This accumulates the clicks and is
not very good.... :-(

I'll try now to spot the bug.

Cheers,
Benjamin

On Sun, Aug 26, 2012 at 2:57 PM, Henrik Rydberg <rydberg@xxxxxxxxxxx> wrote:
> With the input_mt_sync_frame() function in place, there is no longer
> any need to keep the full touch state in the driver. This patch
> removes the slot state and replaces the lookup code with the input-mt
> equivalent. The initialization code is moved to mt_input_configured(),
> to make sure the full HID report has been seen.
>
> Cc: Benjamin Tissoires <benjamin.tissoires@xxxxxxx>
> Signed-off-by: Henrik Rydberg <rydberg@xxxxxxxxxxx>
> ---
>  drivers/hid/hid-multitouch.c | 133 +++++++++++++++----------------------------
>  1 file changed, 46 insertions(+), 87 deletions(-)
>
> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
> index c400d90..dc08a4e 100644
> --- a/drivers/hid/hid-multitouch.c
> +++ b/drivers/hid/hid-multitouch.c
> @@ -56,7 +56,6 @@ struct mt_slot {
>         __s32 x, y, p, w, h;
>         __s32 contactid;        /* the device ContactID assigned to this slot */
>         bool touch_state;       /* is the touch valid? */
> -       bool seen_in_this_frame;/* has this slot been updated */
>  };
>
>  struct mt_class {
> @@ -93,7 +92,7 @@ struct mt_device {
>                                 * 1 means we should use a serial protocol
>                                 * > 1 means hybrid (multitouch) protocol */
>         bool curvalid;          /* is the current contact valid? */
> -       struct mt_slot *slots;
> +       unsigned mt_flags;      /* flags to pass to input-mt */
>  };
>
>  /* classes of device behavior */
> @@ -134,25 +133,6 @@ static int cypress_compute_slot(struct mt_device *td)
>                 return -1;
>  }
>
> -static int find_slot_from_contactid(struct mt_device *td)
> -{
> -       int i;
> -       for (i = 0; i < td->maxcontacts; ++i) {
> -               if (td->slots[i].contactid == td->curdata.contactid &&
> -                       td->slots[i].touch_state)
> -                       return i;
> -       }
> -       for (i = 0; i < td->maxcontacts; ++i) {
> -               if (!td->slots[i].seen_in_this_frame &&
> -                       !td->slots[i].touch_state)
> -                       return i;
> -       }
> -       /* should not occurs. If this happens that means
> -        * that the device sent more touches that it says
> -        * in the report descriptor. It is ignored then. */
> -       return -1;
> -}
> -
>  static struct mt_class mt_classes[] = {
>         { .name = MT_CLS_DEFAULT,
>                 .quirks = MT_QUIRK_NOT_SEEN_MEANS_UP },
> @@ -319,24 +299,16 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
>         * We need to ignore fields that belong to other collections
>         * such as Mouse that might have the same GenericDesktop usages. */
>         if (field->application == HID_DG_TOUCHSCREEN)
> -               set_bit(INPUT_PROP_DIRECT, hi->input->propbit);
> +               td->mt_flags |= INPUT_MT_DIRECT;
>         else if (field->application != HID_DG_TOUCHPAD)
>                 return 0;
>
> -       /* In case of an indirect device (touchpad), we need to add
> -        * specific BTN_TOOL_* to be handled by the synaptics xorg
> -        * driver.
> -        * We also consider that touchscreens providing buttons are touchpads.
> +       /*
> +        * Model touchscreens providing buttons as touchpads.
>          */
>         if (field->application == HID_DG_TOUCHPAD ||
> -           (usage->hid & HID_USAGE_PAGE) == HID_UP_BUTTON ||
> -           cls->is_indirect) {
> -               set_bit(INPUT_PROP_POINTER, hi->input->propbit);
> -               set_bit(BTN_TOOL_FINGER, hi->input->keybit);
> -               set_bit(BTN_TOOL_DOUBLETAP, hi->input->keybit);
> -               set_bit(BTN_TOOL_TRIPLETAP, hi->input->keybit);
> -               set_bit(BTN_TOOL_QUADTAP, hi->input->keybit);
> -       }
> +           (usage->hid & HID_USAGE_PAGE) == HID_UP_BUTTON)
> +               td->mt_flags |= INPUT_MT_POINTER;
>
>         /* eGalax devices provide a Digitizer.Stylus input which overrides
>          * the correct Digitizers.Finger X/Y ranges.
> @@ -353,8 +325,6 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
>                                         EV_ABS, ABS_MT_POSITION_X);
>                         set_abs(hi->input, ABS_MT_POSITION_X, field,
>                                 cls->sn_move);
> -                       /* touchscreen emulation */
> -                       set_abs(hi->input, ABS_X, field, cls->sn_move);
>                         mt_store_field(usage, td, hi);
>                         td->last_field_index = field->index;
>                         return 1;
> @@ -363,8 +333,6 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
>                                         EV_ABS, ABS_MT_POSITION_Y);
>                         set_abs(hi->input, ABS_MT_POSITION_Y, field,
>                                 cls->sn_move);
> -                       /* touchscreen emulation */
> -                       set_abs(hi->input, ABS_Y, field, cls->sn_move);
>                         mt_store_field(usage, td, hi);
>                         td->last_field_index = field->index;
>                         return 1;
> @@ -390,7 +358,6 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
>                 case HID_DG_CONTACTID:
>                         if (!td->maxcontacts)
>                                 td->maxcontacts = MT_DEFAULT_MAXCONTACT;
> -                       input_mt_init_slots(hi->input, td->maxcontacts, 0);
>                         mt_store_field(usage, td, hi);
>                         td->last_field_index = field->index;
>                         td->touches_by_report++;
> @@ -418,9 +385,6 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
>                                         EV_ABS, ABS_MT_PRESSURE);
>                         set_abs(hi->input, ABS_MT_PRESSURE, field,
>                                 cls->sn_pressure);
> -                       /* touchscreen emulation */
> -                       set_abs(hi->input, ABS_PRESSURE, field,
> -                               cls->sn_pressure);
>                         mt_store_field(usage, td, hi);
>                         td->last_field_index = field->index;
>                         return 1;
> @@ -464,7 +428,24 @@ static int mt_input_mapped(struct hid_device *hdev, struct hid_input *hi,
>         return -1;
>  }
>
> -static int mt_compute_slot(struct mt_device *td)
> +static void mt_input_configured(struct hid_device *hdev, struct hid_input *hi)
> +
> +{
> +       struct mt_device *td = hid_get_drvdata(hdev);
> +       struct mt_class *cls = &td->mtclass;
> +
> +       if (cls->is_indirect)
> +               td->mt_flags |= INPUT_MT_POINTER;
> +
> +       if (cls->quirks & MT_QUIRK_NOT_SEEN_MEANS_UP)
> +               td->mt_flags |= INPUT_MT_DROP_UNUSED;
> +
> +       input_mt_init_slots(hi->input, td->maxcontacts, td->mt_flags);
> +
> +       td->mt_flags = 0;
> +}
> +
> +static int mt_compute_slot(struct mt_device *td, struct input_dev *input)
>  {
>         __s32 quirks = td->mtclass.quirks;
>
> @@ -480,42 +461,23 @@ static int mt_compute_slot(struct mt_device *td)
>         if (quirks & MT_QUIRK_SLOT_IS_CONTACTID_MINUS_ONE)
>                 return td->curdata.contactid - 1;
>
> -       return find_slot_from_contactid(td);
> +       return input_mt_assign_slot_by_id(input, td->curdata.contactid);
>  }
>
>  /*
>   * this function is called when a whole contact has been processed,
>   * so that it can assign it to a slot and store the data there
>   */
> -static void mt_complete_slot(struct mt_device *td)
> +static void mt_complete_slot(struct mt_device *td, struct input_dev *input)
>  {
> -       td->curdata.seen_in_this_frame = true;
>         if (td->curvalid) {
> -               int slotnum = mt_compute_slot(td);
> -
> -               if (slotnum >= 0 && slotnum < td->maxcontacts)
> -                       td->slots[slotnum] = td->curdata;
> -       }
> -       td->num_received++;
> -}
> +               int slotnum = mt_compute_slot(td, input);
> +               struct mt_slot *s = &td->curdata;
>
> +               if (slotnum < 0 || slotnum >= td->maxcontacts)
> +                       return;
>
> -/*
> - * this function is called when a whole packet has been received and processed,
> - * so that it can decide what to send to the input layer.
> - */
> -static void mt_emit_event(struct mt_device *td, struct input_dev *input)
> -{
> -       int i;
> -
> -       for (i = 0; i < td->maxcontacts; ++i) {
> -               struct mt_slot *s = &(td->slots[i]);
> -               if ((td->mtclass.quirks & MT_QUIRK_NOT_SEEN_MEANS_UP) &&
> -                       !s->seen_in_this_frame) {
> -                       s->touch_state = false;
> -               }
> -
> -               input_mt_slot(input, i);
> +               input_mt_slot(input, slotnum);
>                 input_mt_report_slot_state(input, MT_TOOL_FINGER,
>                         s->touch_state);
>                 if (s->touch_state) {
> @@ -532,16 +494,22 @@ static void mt_emit_event(struct mt_device *td, struct input_dev *input)
>                         input_event(input, EV_ABS, ABS_MT_TOUCH_MAJOR, major);
>                         input_event(input, EV_ABS, ABS_MT_TOUCH_MINOR, minor);
>                 }
> -               s->seen_in_this_frame = false;
> -
>         }
>
> -       input_mt_report_pointer_emulation(input, true);
> -       input_sync(input);
> -       td->num_received = 0;
> +       td->num_received++;
>  }
>
>
> +/*
> + * this function is called when a whole packet has been received and processed,
> + * so that it can decide what to send to the input layer.
> + */
> +static void mt_sync_frame(struct mt_device *td, struct input_dev *input)
> +{
> +       input_mt_sync_frame(input);
> +       input_sync(input);
> +       td->num_received = 0;
> +}
>
>  static int mt_event(struct hid_device *hid, struct hid_field *field,
>                                 struct hid_usage *usage, __s32 value)
> @@ -549,7 +517,7 @@ static int mt_event(struct hid_device *hid, struct hid_field *field,
>         struct mt_device *td = hid_get_drvdata(hid);
>         __s32 quirks = td->mtclass.quirks;
>
> -       if (hid->claimed & HID_CLAIMED_INPUT && td->slots) {
> +       if (hid->claimed & HID_CLAIMED_INPUT) {
>                 switch (usage->hid) {
>                 case HID_DG_INRANGE:
>                         if (quirks & MT_QUIRK_ALWAYS_VALID)
> @@ -602,11 +570,11 @@ static int mt_event(struct hid_device *hid, struct hid_field *field,
>                 }
>
>                 if (usage->hid == td->last_slot_field)
> -                       mt_complete_slot(td);
> +                       mt_complete_slot(td, field->hidinput->input);
>
>                 if (field->index == td->last_field_index
>                         && td->num_received >= td->num_expected)
> -                       mt_emit_event(td, field->hidinput->input);
> +                       mt_sync_frame(td, field->hidinput->input);
>
>         }
>
> @@ -735,15 +703,6 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
>         if (id->vendor == HID_ANY_ID && id->product == HID_ANY_ID)
>                 mt_post_parse_default_settings(td);
>
> -       td->slots = kzalloc(td->maxcontacts * sizeof(struct mt_slot),
> -                               GFP_KERNEL);
> -       if (!td->slots) {
> -               dev_err(&hdev->dev, "cannot allocate multitouch slots\n");
> -               hid_hw_stop(hdev);
> -               ret = -ENOMEM;
> -               goto fail;
> -       }
> -
>         ret = sysfs_create_group(&hdev->dev.kobj, &mt_attribute_group);
>
>         mt_set_maxcontacts(hdev);
> @@ -774,7 +733,6 @@ static void mt_remove(struct hid_device *hdev)
>         struct mt_device *td = hid_get_drvdata(hdev);
>         sysfs_remove_group(&hdev->dev.kobj, &mt_attribute_group);
>         hid_hw_stop(hdev);
> -       kfree(td->slots);
>         kfree(td);
>         hid_set_drvdata(hdev, NULL);
>  }
> @@ -1087,6 +1045,7 @@ static struct hid_driver mt_driver = {
>         .remove = mt_remove,
>         .input_mapping = mt_input_mapping,
>         .input_mapped = mt_input_mapped,
> +       .input_configured = mt_input_configured,
>         .feature_mapping = mt_feature_mapping,
>         .usage_table = mt_grabbed_usages,
>         .event = mt_event,
> --
> 1.7.12
>
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