From 55bbb28a8010135809a7499f22aed1f6c6a7c004 Mon Sep 17 00:00:00 2001
From: Marco Rodolfi <marco.rodolfi@tuta.io>
Date: Thu, 16 Jan 2025 16:19:31 +0100
Subject: [PATCH] [threading] Linux fixes on setting an incorrect priority

This call was failing since SCHED_FIFO doesn't support negative priorities, but only positive ones, see third paragraph of scheduling policies: https://man7.org/linux/man-pages/man7/sched.7.html.

Additionally Linux do provice up to 99 levels, but I've limited myself to the required UNIX standard of 32, and split the priority levels evenly from that.

I've also added a couple of rows to debug additional issues in the future like this.
---
 src/xenia/base/threading.h        | 10 ++++++++++
 src/xenia/base/threading_posix.cc | 16 ++++++++++++++--
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/src/xenia/base/threading.h b/src/xenia/base/threading.h
index a145c3830..26e5267bf 100644
--- a/src/xenia/base/threading.h
+++ b/src/xenia/base/threading.h
@@ -402,6 +402,7 @@ class Timer : public WaitHandle {
   virtual bool Cancel() = 0;
 };
 
+#if XE_PLATFORM_WINDOWS
 struct ThreadPriority {
   static const int32_t kLowest = -2;
   static const int32_t kBelowNormal = -1;
@@ -409,6 +410,15 @@ struct ThreadPriority {
   static const int32_t kAboveNormal = 1;
   static const int32_t kHighest = 2;
 };
+#else
+struct ThreadPriority {
+  static const int32_t kLowest = 1;
+  static const int32_t kBelowNormal = 8;
+  static const int32_t kNormal = 16;
+  static const int32_t kAboveNormal = 24;
+  static const int32_t kHighest = 32;
+};
+#endif
 
 // Models a Win32-like thread object.
 // https://msdn.microsoft.com/en-us/library/windows/desktop/ms682453(v=vs.85).aspx
diff --git a/src/xenia/base/threading_posix.cc b/src/xenia/base/threading_posix.cc
index f72f72d6f..733592800 100644
--- a/src/xenia/base/threading_posix.cc
+++ b/src/xenia/base/threading_posix.cc
@@ -27,6 +27,8 @@
 #include <ctime>
 #include <memory>
 
+#include "logging.h"
+
 #if XE_PLATFORM_ANDROID
 #include <dlfcn.h>
 
@@ -660,8 +662,18 @@ class PosixCondition<Thread> : public PosixConditionBase {
     WaitStarted();
     sched_param param{};
     param.sched_priority = new_priority;
-    if (pthread_setschedparam(thread_, SCHED_FIFO, &param) != 0)
-      assert_always();
+    int res = pthread_setschedparam(thread_, SCHED_FIFO, &param);
+    if (res != 0) {
+      switch (res) {
+        case EPERM:
+          XELOGW("Permission denied while setting priority");
+          break;
+        case EINVAL:
+          assert_always();
+        default:
+          XELOGW("Unknown error while setting priority");
+      }
+    }
   }
 
   void QueueUserCallback(std::function<void()> callback) {