From c28311fc97ef8d46a0e796cf475b7e80de895a31 Mon Sep 17 00:00:00 2001
From: Wim Taymans <wtaymans@redhat.com>
Date: Wed, 24 Jan 2024 17:53:15 +0100
Subject: [PATCH] support: add resync.ms option to node.driver

Move some of the tracking code for the DLL to where it is used.

Add resync.ms (default 10) option at which we give up rate adjusting
and instead do a hard resync. This results in a jump in the position
of the graph clock.
---
 spa/include/spa/utils/defs.h      |  4 ++++
 spa/plugins/support/node-driver.c | 29 ++++++++++++++++++++---------
 src/daemon/pipewire-aes67.conf.in |  1 +
 3 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/spa/include/spa/utils/defs.h b/spa/include/spa/utils/defs.h
index 8940b52df..393b1f334 100644
--- a/spa/include/spa/utils/defs.h
+++ b/spa/include/spa/utils/defs.h
@@ -156,6 +156,10 @@ struct spa_fraction {
 ({							\
 	fminf(fmaxf(v, low), high);			\
 })
+#define SPA_CLAMPD(v,low,high)				\
+({							\
+	fmin(fmax(v, low), high);			\
+})
 
 
 #define SPA_SWAP(a,b)					\
diff --git a/spa/plugins/support/node-driver.c b/spa/plugins/support/node-driver.c
index dc36c8216..4c03fa8bb 100644
--- a/spa/plugins/support/node-driver.c
+++ b/spa/plugins/support/node-driver.c
@@ -33,6 +33,7 @@
 #define DEFAULT_FREEWHEEL_WAIT	10
 #define DEFAULT_CLOCK_PREFIX	"clock.system"
 #define DEFAULT_CLOCK_ID	CLOCK_MONOTONIC
+#define DEFAULT_RESYNC_MS	10
 
 #define CLOCKFD 3
 #define FD_TO_CLOCKID(fd)	((~(clockid_t) (fd) << 3) | CLOCKFD)
@@ -46,6 +47,7 @@ struct props {
 	char clock_name[64];
 	clockid_t clock_id;
 	uint32_t freewheel_wait;
+	uint32_t resync_ms;
 };
 
 struct impl {
@@ -81,6 +83,7 @@ struct impl {
 	uint64_t base_time;
 	struct spa_dll dll;
 	double max_error;
+	double max_resync;
 };
 
 static void reset_props(struct props *props)
@@ -89,6 +92,7 @@ static void reset_props(struct props *props)
 	spa_zero(props->clock_name);
 	props->clock_id = CLOCK_MONOTONIC;
 	props->freewheel_wait = DEFAULT_FREEWHEEL_WAIT;
+	props->resync_ms = DEFAULT_RESYNC_MS;
 }
 
 static const struct clock_info {
@@ -281,6 +285,7 @@ static void on_timeout(struct spa_source *source)
 	if (this->last_time == 0) {
 		spa_dll_set_bw(&this->dll, SPA_DLL_BW_MIN, duration, rate);
 		this->max_error = rate * MAX_ERROR_MS / 1000;
+		this->max_resync = rate * this->props.resync_ms / 1000;
 		position = current_position;
 	} else if (SPA_LIKELY(this->clock)) {
 		position = this->clock->position + this->clock->duration;
@@ -288,21 +293,25 @@ static void on_timeout(struct spa_source *source)
 		position = current_position;
 	}
 
-	/* check the elapsed time of the other clock against
-	 * the graph clock elapsed time, feed this error into the
-	 * dll and adjust the timeout of our MONOTONIC clock. */
-	err = (double)position - (double)current_position;
-	if (err > this->max_error)
-		err = this->max_error;
-	else if (err < -this->max_error)
-		err = -this->max_error;
-
 	this->last_time = current_time;
 
 	if (this->props.freewheel) {
 		corr = 1.0;
 		this->next_time = nsec + this->props.freewheel_wait * SPA_NSEC_PER_SEC;
 	} else if (this->tracking) {
+		/* check the elapsed time of the other clock against
+		 * the graph clock elapsed time, feed this error into the
+		 * dll and adjust the timeout of our MONOTONIC clock. */
+		err = (double)position - (double)current_position;
+		if (fabs(err) > this->max_error) {
+			if (fabs(err) > this->max_resync) {
+				spa_dll_set_bw(&this->dll, SPA_DLL_BW_MIN, duration, rate);
+				position = current_position;
+				err = 0.0;
+			} else {
+				err = SPA_CLAMPD(err, -this->max_error, this->max_error);
+			}
+		}
 		corr = spa_dll_update(&this->dll, err);
 		this->next_time = nsec + duration / corr * 1e9 / rate;
 	} else {
@@ -621,6 +630,8 @@ impl_init(const struct spa_handle_factory *factory,
 			}
 		} else if (spa_streq(k, "freewheel.wait")) {
 			this->props.freewheel_wait = atoi(s);
+		} else if (spa_streq(k, "resync.ms")) {
+			this->props.resync_ms = atoi(s);
 		}
 	}
 	if (this->props.clock_name[0] == '\0') {
diff --git a/src/daemon/pipewire-aes67.conf.in b/src/daemon/pipewire-aes67.conf.in
index 3b7e711e0..ea39d09e6 100644
--- a/src/daemon/pipewire-aes67.conf.in
+++ b/src/daemon/pipewire-aes67.conf.in
@@ -39,6 +39,7 @@ context.objects = [
             #clock.id        = tai
             clock.device    = "/dev/ptp0"
             #clock.interface = "eth0"
+            #resync.ms       = 10
             object.export   = true
         }
     }