From 4419baec45145c3ad58e18c242f18bbf3c56b5f9 Mon Sep 17 00:00:00 2001
From: Robbert van der Helm <mail@robbertvanderhelm.nl>
Date: Sun, 16 Jan 2022 16:49:03 +0100
Subject: [PATCH] module-rt: Use magic value for user config prio

Instead of having the context priority hardcoded at 88.
---
 spa/include/spa/support/thread.h | 4 +++-
 src/modules/module-rt.c          | 5 +++++
 src/pipewire/context.c           | 3 ++-
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/spa/include/spa/support/thread.h b/spa/include/spa/support/thread.h
index 158fd4fc5..1bff45080 100644
--- a/spa/include/spa/support/thread.h
+++ b/spa/include/spa/support/thread.h
@@ -68,7 +68,9 @@ struct spa_thread_utils_methods {
 
 	/** get realtime priority range for threads created with \a props */
 	int (*get_rt_range) (void *data, const struct spa_dict *props, int *min, int *max);
-	/** acquire realtime priority */
+	/** acquire realtime priority, a priority of -1 refers to the priority
+	 * configured in the realtime module
+	 */
 	int (*acquire_rt) (void *data, struct spa_thread *thread, int priority);
 	/** drop realtime priority */
 	int (*drop_rt) (void *data, struct spa_thread *thread);
diff --git a/src/modules/module-rt.c b/src/modules/module-rt.c
index 23458b592..a16405235 100644
--- a/src/modules/module-rt.c
+++ b/src/modules/module-rt.c
@@ -682,6 +682,11 @@ static int impl_acquire_rt(void *data, struct spa_thread *thread, int priority)
 	pthread_t pt = (pthread_t)thread;
 	pid_t pid;
 
+	// See the docstring on `spa_thread_utils_methods::acquire_rt`
+	if (priority == -1) {
+		priority = impl->rt_prio;
+	}
+
 	if (impl->use_rtkit) {
 		rtprio_limit = pw_rtkit_get_max_realtime_priority(impl->system_bus);
 		if (rtprio_limit >= 0)
diff --git a/src/pipewire/context.c b/src/pipewire/context.c
index 365f39a42..123a7ba54 100644
--- a/src/pipewire/context.c
+++ b/src/pipewire/context.c
@@ -134,7 +134,8 @@ static int context_set_freewheel(struct pw_context *context, bool freewheel)
 		res = pw_thread_utils_drop_rt(thr);
 	} else {
 		pw_log_info("%p: exit freewheel", context);
-		res = pw_thread_utils_acquire_rt(thr, 88);
+		// Use the priority as configured within the realtime module
+		res = pw_thread_utils_acquire_rt(thr, -1);
 	}
 	if (res < 0)
 		pw_log_info("%p: freewheel error:%s", context, spa_strerror(res));