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authorJason Gerecke2022-01-18 14:37:56 -0800
committerJiri Kosina2022-01-21 15:10:02 +0100
commitdf03e9bd6d4806619b4cdc91a3d7695818a8e2b7 (patch)
treee49f3b3fdc5c5871e2e5c817414da92760dfc9cf /drivers/hid
parent546e41ac994cc185ef3de610ca849a294b5df3ba (diff)
HID: wacom: Ignore the confidence flag when a touch is removed
AES hardware may internally re-classify a contact that it thought was intentional as a palm. Intentional contacts are reported as "down" with the confidence bit set. When this re-classification occurs, however, the state transitions to "up" with the confidence bit cleared. This kind of transition appears to be legal according to Microsoft docs, but we do not handle it correctly. Because the confidence bit is clear, we don't call `wacom_wac_finger_slot` and update userspace. This causes hung touches that confuse userspace and interfere with pen arbitration. This commit adds a special case to ignore the confidence flag if a contact is reported as removed. This ensures we do not leave a hung touch if one of these re-classification events occured. Ideally we'd have some way to also let userspace know that the touch has been re-classified as a palm and needs to be canceled, but that's not possible right now :) Link: https://github.com/linuxwacom/input-wacom/issues/288 Fixes: 7fb0413baa7f (HID: wacom: Use "Confidence" flag to prevent reporting invalid contacts) CC: stable@vger.kernel.org Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com> Reviewed-by: Ping Cheng <ping.cheng@wacom.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'drivers/hid')
-rw-r--r--drivers/hid/wacom_wac.c29
1 files changed, 26 insertions, 3 deletions
diff --git a/drivers/hid/wacom_wac.c b/drivers/hid/wacom_wac.c
index 5978399ae7d2..92b52b1de526 100644
--- a/drivers/hid/wacom_wac.c
+++ b/drivers/hid/wacom_wac.c
@@ -2588,6 +2588,24 @@ static void wacom_wac_finger_slot(struct wacom_wac *wacom_wac,
}
}
+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)
{
@@ -2638,9 +2656,14 @@ static void wacom_wac_finger_event(struct hid_device *hdev,
}
if (usage->usage_index + 1 == field->report_count) {
- if (equivalent_usage == wacom_wac->hid_data.last_slot_field &&
- wacom_wac->hid_data.confidence)
- wacom_wac_finger_slot(wacom_wac, wacom_wac->touch_input);
+ 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);
+ }
+ }
}
}