This is a note to let you know that I've just added the patch titled
HID: wacom: Correct behavior when processing some confidence == false touches
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
hid-wacom-correct-behavior-when-processing-some-confidence-false-touches.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 502296030ec6b0329e00f9fb15018e170cc63037 Mon Sep 17 00:00:00 2001
From: Jason Gerecke <jason.gerecke@xxxxxxxxx>
Date: Tue, 19 Dec 2023 13:33:43 -0800
Subject: HID: wacom: Correct behavior when processing some confidence == false touches
From: Jason Gerecke <jason.gerecke@xxxxxxxxx>
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@xxxxxxxxx>
Signed-off-by: Ping Cheng <ping.cheng@xxxxxxxxx>
Signed-off-by: Jason Gerecke <jason.gerecke@xxxxxxxxx>
Fixes: 7fb0413baa7f ("HID: wacom: Use "Confidence" flag to prevent reporting invalid contacts")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jiri Kosina <jkosina@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -2612,8 +2612,8 @@ 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) {
@@ -2652,24 +2652,6 @@ 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)
{
@@ -2717,14 +2699,8 @@ 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);
}
}
Patches currently in stable-queue which might be from jason.gerecke@xxxxxxxxx are
queue-5.4/hid-wacom-correct-behavior-when-processing-some-confidence-false-touches.patch
