From 9cc609c4b0679f6a22d08da4ea3644ea96035d9d Mon Sep 17 00:00:00 2001
From: Miroslav Lichvar <mlichvar@redhat.com>
Date: Thu, 12 May 2022 11:53:15 +0200
Subject: [PATCH] local: cancel remaining correction after external step

Instead of the generic clock driver silently zeroing the remaining
offset after detecting an external step, cancel it properly with the
slew handlers in order to correct timestamps that are not reset in
handling of the unknown step (e.g. the NTP local TX).
---
 local.c       | 2 ++
 sys_generic.c | 7 +------
 2 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/local.c b/local.c
index 80fb6ba..b32d0c6 100644
--- a/local.c
+++ b/local.c
@@ -563,6 +563,8 @@ void
 LCL_NotifyExternalTimeStep(struct timespec *raw, struct timespec *cooked,
     double offset, double dispersion)
 {
+  LCL_CancelOffsetCorrection();
+
   /* Dispatch to all handlers */
   invoke_parameter_change_handlers(raw, cooked, 0.0, offset, LCL_ChangeUnknownStep);
 
diff --git a/sys_generic.c b/sys_generic.c
index 6e29ee2..2e79a1b 100644
--- a/sys_generic.c
+++ b/sys_generic.c
@@ -109,12 +109,7 @@ static void
 handle_step(struct timespec *raw, struct timespec *cooked, double dfreq,
             double doffset, LCL_ChangeType change_type, void *anything)
 {
-  if (change_type == LCL_ChangeUnknownStep) {
-    /* Reset offset and slewing */
-    slew_start = *raw;
-    offset_register = 0.0;
-    update_slew();
-  } else if (change_type == LCL_ChangeStep) {
+  if (change_type == LCL_ChangeStep) {
     UTI_AddDoubleToTimespec(&slew_start, -doffset, &slew_start);
   }
 }