On Thu, Jun 21, 2018 at 02:09:06PM +0200, Benjamin Tissoires wrote: > From: Dmitry Torokhov <[email protected]> > > 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.
tbh. I have a queasy feeling about this last bit. MT_TOOL_PALM has shown to not be reliable on some devices (X1 Carbon 6th) and we mask it out on those. Changing the major/minor means it's impossible to rely on the touch size for palm detection once a device supports MT_TOOL_PALM. Cheers, Peter > > [1] > https://docs.microsoft.com/en-us/windows-hardware/design/component-guidelines/touchpad-windows-precision-touchpad-collection > > Signed-off-by: Dmitry Torokhov <[email protected]> > [splitted and rebased] > Signed-off-by: Benjamin Tissoires <[email protected]> > > --- > > changes in v2: > - dropped the delayed release in case of palm detection. This is > a FW bug for PTP devices, and should only happen with touchscreens > - move input_set_abs_params(hi->input, ABS_MT_TOOL_TYPE,...) into > its own test so other devices can add MT_QUIRK_CONFIDENCE to their > quirks. > > no changes in v3 > --- > drivers/hid/hid-multitouch.c | 30 ++++++++++++++++++++++++------ > 1 file changed, 24 insertions(+), 6 deletions(-) > > diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c > index a4a274ebfbef..36c8b67bb032 100644 > --- a/drivers/hid/hid-multitouch.c > +++ b/drivers/hid/hid-multitouch.c > @@ -736,6 +736,13 @@ static int mt_touch_input_mapping(struct hid_device > *hdev, struct hid_input *hi, > cls->name == MT_CLS_WIN_8_DUAL) && > field->application == HID_DG_TOUCHPAD) > app->quirks |= MT_QUIRK_CONFIDENCE; > + > + if (app->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(confidence_state); > return 1; > case HID_DG_TIPSWITCH: > @@ -958,10 +965,12 @@ static int mt_process_slot(struct mt_device *td, struct > input_dev *input, > if (quirks & MT_QUIRK_HOVERING) > inrange_state = *slot->inrange_state; > > - active = (*slot->tip_state || inrange_state) && confidence_state; > + active = *slot->tip_state || inrange_state; > > if (app->application == HID_GD_SYSTEM_MULTIAXIS) > tool = MT_TOOL_DIAL; > + else if (unlikely(!confidence_state)) > + tool = MT_TOOL_PALM; > > input_mt_slot(input, slotnum); > input_mt_report_slot_state(input, tool, active); > @@ -993,11 +1002,20 @@ static int mt_process_slot(struct mt_device *td, > struct input_dev *input, > orientation = -azimuth; > } > > - /* > - * divided by two to match visual scale of touch > - * for devices with this quirk > - */ > - if (quirks & MT_QUIRK_TOUCH_SIZE_SCALING) { > + if (unlikely(!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 (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; > } > -- > 2.14.3 >
