From e3ea1dd2fe3909a0b7aa9e7489a22aeb1c37b1d5 Mon Sep 17 00:00:00 2001
From: Robbert van der Helm <mail@robbertvanderhelm.nl>
Date: Mon, 11 Jan 2021 14:04:54 +0100
Subject: [PATCH] Allow an option set_realtime_priority() to revert

---
 src/common/utils.cpp              | 5 +++--
 src/common/utils.h                | 5 ++++-
 src/plugin/bridges/common.h       | 2 +-
 src/wine-host/group-host.cpp      | 2 +-
 src/wine-host/individual-host.cpp | 2 +-
 5 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/common/utils.cpp b/src/common/utils.cpp
index 19ced3bf..79c35178 100644
--- a/src/common/utils.cpp
+++ b/src/common/utils.cpp
@@ -31,7 +31,8 @@ fs::path get_temporary_directory() {
     }
 }
 
-bool set_realtime_priority() {
+bool set_realtime_priority(bool sched_fifo) {
     sched_param params{.sched_priority = 5};
-    return sched_setscheduler(0, SCHED_FIFO, &params) == 0;
+    return sched_setscheduler(0, sched_fifo ? SCHED_FIFO : SCHED_OTHER,
+                              &params) == 0;
 }
diff --git a/src/common/utils.h b/src/common/utils.h
index 075eeb5f..239e30b0 100644
--- a/src/common/utils.h
+++ b/src/common/utils.h
@@ -41,7 +41,10 @@ boost::filesystem::path get_temporary_directory();
  * We explicitly don't do this for wineserver itself since from my testing that
  * can actually increase latencies.
  *
+ * @param sched_fifo If true, set the current process/thread's scheudling policy
+ *   to `SCHED_FIFO`. Otherwise reset it back to `SCHWED_OTHER`.
+ *
  * @return Whether the operation was successful or not. This will fail if the
  *   user does not have the privileges to set realtime priorities.
  */
-bool set_realtime_priority();
+bool set_realtime_priority(bool sched_fifo);
diff --git a/src/plugin/bridges/common.h b/src/plugin/bridges/common.h
index 153c0ffd..0cfcf0e3 100644
--- a/src/plugin/bridges/common.h
+++ b/src/plugin/bridges/common.h
@@ -86,7 +86,7 @@ class PluginBridge {
                                             info.windows_plugin_path.string(),
                                         .endpoint_base_dir =
                                             sockets.base_dir.string()}))),
-          has_realtime_priority(set_realtime_priority()),
+          has_realtime_priority(set_realtime_priority(true)),
           wine_io_handler([&]() { io_context.run(); }) {}
 
     virtual ~PluginBridge(){};
diff --git a/src/wine-host/group-host.cpp b/src/wine-host/group-host.cpp
index 9b681c92..9b214ff2 100644
--- a/src/wine-host/group-host.cpp
+++ b/src/wine-host/group-host.cpp
@@ -41,7 +41,7 @@ int __attribute__((visibility("default")))
 __cdecl
 #endif
     main(int argc, char* argv[]) {
-    set_realtime_priority();
+    set_realtime_priority(true);
 
     // Instead of directly hosting a plugin, this process will receive a UNIX
     // domain socket endpoint path that it should listen on to allow yabridge
diff --git a/src/wine-host/individual-host.cpp b/src/wine-host/individual-host.cpp
index 297a4744..569af64c 100644
--- a/src/wine-host/individual-host.cpp
+++ b/src/wine-host/individual-host.cpp
@@ -37,7 +37,7 @@ int __attribute__((visibility("default")))
 __cdecl
 #endif
     main(int argc, char* argv[]) {
-    set_realtime_priority();
+    set_realtime_priority(true);
 
     // We pass plugin format, the name of the VST2 plugin .dll file or VST3
     // bundle to load, and the base directory for the Unix domain socket