4.19-stable review patch. If anyone has any objections, please let me know.
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From: Jason Gerecke jason.gerecke@wacom.com
commit 502296030ec6b0329e00f9fb15018e170cc63037 upstream.
There appear to be a few different ways that Wacom devices can deal with confidence:
1. If the device looses confidence in a touch, it will first clear the tipswitch flag in one report, and then clear the confidence flag in a second report. This behavior is used by e.g. DTH-2452.
2. If the device looses confidence in a touch, it will clear both the tipswitch and confidence flags within the same report. This behavior is used by some AES devices.
3. If the device looses confidence in a touch, it will clear *only* the confidence bit. The tipswitch bit will remain set so long as the touch is tracked. This behavior may be used in future devices.
The driver does not currently handle situation 3 properly. Touches that loose confidence will remain "in prox" and essentially frozen in place until the tipswitch bit is finally cleared. Not only does this result in userspace seeing a stuck touch, but it also prevents pen arbitration from working properly (the pen won't send events until all touches are up, but we don't currently process events from non-confident touches).
This commit centralizes the checking of the confidence bit in the wacom_wac_finger_slot() function and has 'prox' depend on it. In the case where situation 3 is encountered, the treat the touch as though it was removed, allowing both userspace and the pen arbitration to act normally.
Signed-off-by: Tatsunosuke Tobita tatsunosuke.tobita@wacom.com Signed-off-by: Ping Cheng ping.cheng@wacom.com Signed-off-by: Jason Gerecke jason.gerecke@wacom.com Fixes: 7fb0413baa7f ("HID: wacom: Use "Confidence" flag to prevent reporting invalid contacts") Cc: stable@vger.kernel.org Signed-off-by: Jiri Kosina jkosina@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/hid/wacom_wac.c | 32 ++++---------------------------- 1 file changed, 4 insertions(+), 28 deletions(-)
--- a/drivers/hid/wacom_wac.c +++ b/drivers/hid/wacom_wac.c @@ -2533,8 +2533,8 @@ static void wacom_wac_finger_slot(struct { struct hid_data *hid_data = &wacom_wac->hid_data; bool mt = wacom_wac->features.touch_max > 1; - bool prox = hid_data->tipswitch && - report_touch_events(wacom_wac); + bool touch_down = hid_data->tipswitch && hid_data->confidence; + bool prox = touch_down && report_touch_events(wacom_wac);
if (wacom_wac->shared->has_mute_touch_switch && !wacom_wac->shared->is_touch_on) { @@ -2573,24 +2573,6 @@ static void wacom_wac_finger_slot(struct } }
-static bool wacom_wac_slot_is_active(struct input_dev *dev, int key) -{ - struct input_mt *mt = dev->mt; - struct input_mt_slot *s; - - if (!mt) - return false; - - for (s = mt->slots; s != mt->slots + mt->num_slots; s++) { - if (s->key == key && - input_mt_get_value(s, ABS_MT_TRACKING_ID) >= 0) { - return true; - } - } - - return false; -} - static void wacom_wac_finger_event(struct hid_device *hdev, struct hid_field *field, struct hid_usage *usage, __s32 value) { @@ -2633,14 +2615,8 @@ static void wacom_wac_finger_event(struc
if (usage->usage_index + 1 == field->report_count) { - if (equivalent_usage == wacom_wac->hid_data.last_slot_field) { - bool touch_removed = wacom_wac_slot_is_active(wacom_wac->touch_input, - wacom_wac->hid_data.id) && !wacom_wac->hid_data.tipswitch; - - if (wacom_wac->hid_data.confidence || touch_removed) { - wacom_wac_finger_slot(wacom_wac, wacom_wac->touch_input); - } - } + if (equivalent_usage == wacom_wac->hid_data.last_slot_field) + wacom_wac_finger_slot(wacom_wac, wacom_wac->touch_input); } }