From ee9f283d4da2984b1d6815816ddb55463fda25be Mon Sep 17 00:00:00 2001
From: TuxSH <1922548+TuxSH@users.noreply.github.com>
Date: Sat, 21 Jan 2023 20:32:57 +0000
Subject: [PATCH] rosalina: fix rare screen filter race condition

---
 sysmodules/rosalina/source/menu.c                 |  4 ++--
 sysmodules/rosalina/source/menus/screen_filters.c | 13 +++++++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/sysmodules/rosalina/source/menu.c b/sysmodules/rosalina/source/menu.c
index d8c3f39..b630f14 100644
--- a/sysmodules/rosalina/source/menu.c
+++ b/sysmodules/rosalina/source/menu.c
@@ -255,8 +255,8 @@ void menuThreadMain(void)
     if(isN3DS)
         N3DSMenu_UpdateStatus();
 
-    while (!isServiceUsable("ac:u") || !isServiceUsable("hid:USER"))
-        svcSleepThread(500 * 1000 * 1000LL);
+    while (!isServiceUsable("ac:u") || !isServiceUsable("hid:USER") || !isServiceUsable("gsp::Gpu"))
+        svcSleepThread(250 * 1000 * 1000LL);
 
     s64 out = 0;
 
diff --git a/sysmodules/rosalina/source/menus/screen_filters.c b/sysmodules/rosalina/source/menus/screen_filters.c
index a0a9376..bb943d7 100644
--- a/sysmodules/rosalina/source/menus/screen_filters.c
+++ b/sysmodules/rosalina/source/menus/screen_filters.c
@@ -153,13 +153,26 @@ void ScreenFiltersMenu_Set##name(void)\
 
 void ScreenFiltersMenu_RestoreSettings(void)
 {
+    // Precondition: menu has not been entered
+
     // Not initialized/default: return
     if (ScreenFiltersMenu_IsDefaultSettings())
         return;
 
     // Wait for GSP to restore the CCT table
     svcSleepThread(20 * 1000 * 1000LL);
+
+    // Pause GSP, then wait a bit to ensure GPU commands complete
+    // We need to ensure no GPU stuff is running when changing
+    // the gamma table (otherwise colors become and stay glitched).
+    svcKernelSetState(0x10000, 2);
+    svcSleepThread(5 * 1000 * 100LL);
+
     ScreenFiltersMenu_ApplyColorSettings();
+
+    // Unpause GSP
+    svcKernelSetState(0x10000, 2);
+    svcSleepThread(5 * 1000 * 100LL);
 }
 
 DEF_CCT_SETTER(6500, Default)