Hi Dmitry, On Thu, Aug 10, 2017 at 05:44:59PM -0700, Dmitry Torokhov wrote: > According to Microsoft specification [1] for Precision Touchpads (and > Touchscreens) the devices use "confidence" reports to signal accidental > touches, or contacts that are "too large to be a finger". Instead of > simply marking contact inactive in this case (which causes issues if > contact was originally proper and we lost confidence in it later, as > this results in accidental clicks, drags, etc), let's report such > contacts as MT_TOOL_PALM and let userspace decide what to do. > Additionally, let's report contact size for such touches as maximum > allowed for major/minor, which should help userspace that is not yet > aware of MT_TOOL_PALM to still perform palm rejection. > > An additional complication, is that some firmwares do not report > non-confident touches as active. To cope with this we delay release of > such contact (i.e. if contact was active we first report it as still > active MT+TOOL_PALM and then synthesize the release event in a separate > frame). > > [1] > https://docs.microsoft.com/en-us/windows-hardware/design/component-guidelines/touchpad-windows-precision-touchpad-collection > > Signed-off-by: Dmitry Torokhov <dmitry.torok...@gmail.com>
This one popped up again in a bug report [1] and it looks like it never got merged. fwiw, libinput does support ABS_MT_TOOL_PALM for touchpads as of 1.8.0 and just releasing the touch causes fake taps. So you have the green light from me to merge this :) Cheers, Peter [1] https://bugs.freedesktop.org/show_bug.cgi?id=106716 > --- > drivers/hid/hid-multitouch.c | 86 > +++++++++++++++++++++++++++++++++++++++----- > 1 file changed, 77 insertions(+), 9 deletions(-) > > diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c > index 440b999304a5..c28defe50a10 100644 > --- a/drivers/hid/hid-multitouch.c > +++ b/drivers/hid/hid-multitouch.c > @@ -114,6 +114,8 @@ struct mt_device { > struct timer_list release_timer; /* to release sticky fingers */ > struct mt_fields *fields; /* temporary placeholder for storing the > multitouch fields */ > + unsigned long *pending_palm_slots; /* slots where we reported palm > + and need to release */ > unsigned long mt_io_flags; /* mt flags (MT_IO_FLAGS_*) */ > int cc_index; /* contact count field index in the report */ > int cc_value_index; /* contact count value index in the field */ > @@ -543,8 +545,12 @@ 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_DUAL) && > - field->application == HID_DG_TOUCHPAD) > + field->application == HID_DG_TOUCHPAD) { > cls->quirks |= MT_QUIRK_CONFIDENCE; > + input_set_abs_params(hi->input, > + ABS_MT_TOOL_TYPE, > + MT_TOOL_FINGER, MT_TOOL_PALM, 0, 0); > + } > mt_store_field(usage, td, hi); > return 1; > case HID_DG_TIPSWITCH: > @@ -657,6 +663,7 @@ static void mt_complete_slot(struct mt_device *td, struct > input_dev *input) > > if (td->curvalid || (td->mtclass.quirks & MT_QUIRK_ALWAYS_VALID)) { > int active; > + int tool; > int slotnum = mt_compute_slot(td, input); > struct mt_slot *s = &td->curdata; > struct input_mt *mt = input->mt; > @@ -671,24 +678,56 @@ static void mt_complete_slot(struct mt_device *td, > struct input_dev *input) > return; > } > > + active = s->touch_state || s->inrange_state; > + > if (!(td->mtclass.quirks & MT_QUIRK_CONFIDENCE)) > s->confidence_state = 1; > - active = (s->touch_state || s->inrange_state) && > - s->confidence_state; > + > + if (likely(s->confidence_state)) { > + tool = MT_TOOL_FINGER; > + } else { > + tool = MT_TOOL_PALM; > + if (!active && > + input_mt_is_active(&mt->slots[slotnum])) { > + /* > + * The non-confidence was reported for > + * previously valid contact that is also no > + * longer valid. We can't simply report > + * lift-off as userspace will not be aware > + * of non-confidence, so we need to split > + * it into 2 events: active MT_TOOL_PALM > + * and a separate liftoff. > + */ > + active = true; > + set_bit(slotnum, td->pending_palm_slots); > + } > + } > > input_mt_slot(input, slotnum); > - input_mt_report_slot_state(input, MT_TOOL_FINGER, active); > + input_mt_report_slot_state(input, tool, active); > if (active) { > /* this finger is in proximity of the sensor */ > int wide = (s->w > s->h); > int major = max(s->w, s->h); > int minor = min(s->w, s->h); > > - /* > - * divided by two to match visual scale of touch > - * for devices with this quirk > - */ > - if (td->mtclass.quirks & MT_QUIRK_TOUCH_SIZE_SCALING) { > + if (unlikely(!s->confidence_state)) { > + /* > + * When reporting palm, set contact to maximum > + * size to help userspace that does not > + * recognize MT_TOOL_PALM to reject contacts > + * that are too large. > + */ > + major = input_abs_get_max(input, > + ABS_MT_TOUCH_MAJOR); > + minor = input_abs_get_max(input, > + ABS_MT_TOUCH_MINOR); > + } else if (td->mtclass.quirks & > + MT_QUIRK_TOUCH_SIZE_SCALING) { > + /* > + * divided by two to match visual scale of touch > + * for devices with this quirk > + */ > major = major >> 1; > minor = minor >> 1; > } > @@ -711,6 +750,25 @@ static void mt_complete_slot(struct mt_device *td, > struct input_dev *input) > td->num_received++; > } > > +static void mt_release_pending_palms(struct mt_device *td, > + struct input_dev *input) > +{ > + int slotnum; > + bool need_sync = false; > + > + for_each_set_bit(slotnum, td->pending_palm_slots, td->maxcontacts) { > + clear_bit(slotnum, td->pending_palm_slots); > + > + input_mt_slot(input, slotnum); > + input_mt_report_slot_state(input, MT_TOOL_PALM, false); > + > + need_sync = true; > + } > + > + if (need_sync) > + input_sync(input); > +} > + > /* > * 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. > @@ -719,6 +777,9 @@ static void mt_sync_frame(struct mt_device *td, struct > input_dev *input) > { > input_mt_sync_frame(input); > input_sync(input); > + > + mt_release_pending_palms(td, input); > + > td->num_received = 0; > if (test_bit(MT_IO_FLAGS_ACTIVE_SLOTS, &td->mt_io_flags)) > set_bit(MT_IO_FLAGS_PENDING_SLOTS, &td->mt_io_flags); > @@ -903,6 +964,13 @@ static int mt_touch_input_configured(struct hid_device > *hdev, > if (td->is_buttonpad) > __set_bit(INPUT_PROP_BUTTONPAD, input->propbit); > > + td->pending_palm_slots = devm_kcalloc(&hi->input->dev, > + BITS_TO_LONGS(td->maxcontacts), > + sizeof(long), > + GFP_KERNEL); > + if (!td->pending_palm_slots) > + return -ENOMEM; > + > ret = input_mt_init_slots(input, td->maxcontacts, td->mt_flags); > if (ret) > return ret; > -- > 2.14.0.434.g98096fd7a8-goog > > -- > To unsubscribe from this list: send the line "unsubscribe linux-input" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
