git: e3201cec8381 - main - psm: Fix three finger tap on elantech v4 touchpads

The branch main has been updated by wulf:

URL: https://cgit.FreeBSD.org/src/commit/?id=e3201cec8381c0582374f93991eff4a71bb95e9b

commit e3201cec8381c0582374f93991eff4a71bb95e9b
Author:     Robert Wahlberg <freebsd@robertwahlberg.se>
AuthorDate: 2025-12-01 20:42:15 +0000
Commit:     Vladimir Kondratyev <wulf@FreeBSD.org>
CommitDate: 2025-12-01 20:42:15 +0000

    psm: Fix three finger tap on elantech v4 touchpads
    
    Fix an issue where a three finger tap would generate additional events
    when fingers moved slightly during the tap.
    
    Signed-off-by:  Robert Wahlberg <freebsd@robertwahlberg.se>
    Pull Request:   https://github.com/freebsd/freebsd-src/pull/1792
    Reviewed by:    wulf
    MFC after:      1 month
---
 sys/dev/atkbdc/psm.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/sys/dev/atkbdc/psm.c b/sys/dev/atkbdc/psm.c
index 137758b104d3..d36396df0fa0 100644
--- a/sys/dev/atkbdc/psm.c
+++ b/sys/dev/atkbdc/psm.c
@@ -4666,6 +4666,13 @@ proc_elantech(struct psm_softc *sc, packetbuf_t *pb, mousestatus_t *ms,
 		mask = sc->elanaction.mask;
 		nfingers = bitcount(mask);
 
+		/* The motion packet can only update two fingers at a time.
+		 * Copy the previous state to get all active fingers. */
+		for (id = 0; id < ELANTECH_MAX_FINGERS; id++)
+			if (sc->elanaction.mask & (1 << id))
+				f[id] = sc->elanaction.fingers[id];
+
+		/* Update finger positions from the new packet */
 		scale = (pb->ipacket[0] & 0x10) ? 5 : 1;
 		for (i = 0; i <= 3; i += 3) {
 			id = ((pb->ipacket[i] & 0xe0) >> 5) - 1;