From b878201f334b08acfbe02ea431f36a8e928bfdbc Mon Sep 17 00:00:00 2001
From: Takoroka <137927095+Takoroka@users.noreply.github.com>
Date: Sat, 31 Oct 2026 03:02:19 -0400
Subject: nx2: answer vi2 display queries with full replies

103 QueryDisplayRefreshRate replies with the rate and a bool (two words),
104 QueryDisplayHdrStatus with the output format and a u16, 105
QueryDisplayHdrPaperWhite with a u16. 104 and 105 were empty replies and 103
an auto stub, so the sdk read whatever the message buffer held: Minecraft
polled 103 forever (the sdk only accepts 60 or 120) and Kirby Air Riders took
leftover words as an HDR output format and rebuilt its window images. Report
60 Hz, SDR output and the BT.2408 reference white.
---
 src/core/hle/service/nx2_gsv.h | 40 +++++++++++++++++++++++++++++-----------
 1 file changed, 29 insertions(+), 11 deletions(-)

(limited to 'src/core')

diff --git a/src/core/hle/service/nx2_gsv.h b/src/core/hle/service/nx2_gsv.h
index 08f321f133..1abe0baa2c 100644
--- a/src/core/hle/service/nx2_gsv.h
+++ b/src/core/hle/service/nx2_gsv.h
@@ -1419,11 +1419,12 @@ public:
             {270, &INx2Vi2Session::UnbindNativeEvent, "UnbindDisplayBufferMaxResolutionEvent"},
             {271, &INx2Vi2Session::BindChange, "BindDisplayModeCapabilityEvent"},
             {272, &INx2Vi2Session::UnbindNativeEvent, "UnbindDisplayModeCapabilityEvent"},
-            // Title 1 calls these ~75 times a second with the display name "default"; the
-            // auto stub's empty success reply works, but logged two lines per call (a 50 MB log
-            // in an 18 minute session).
-            {104, &INx2Vi2Session::SucceedQuietly, "Unknown104 (display \"default\")"},
-            {105, &INx2Vi2Session::SucceedQuietly, "Unknown105 (display \"default\")"},
+            // Title 1 calls these ~75 times a second with the display name "default"; quiet
+            // handlers (the auto stub logged two lines per call: a 50 MB log in an 18 minute
+            // session).
+            {103, &INx2Vi2Session::QueryDisplayRefreshRate, "QueryDisplayRefreshRate"},
+            {104, &INx2Vi2Session::QueryDisplayHdrStatus, "QueryDisplayHdrStatus"},
+            {105, &INx2Vi2Session::QueryDisplayHdrPaperWhite, "QueryDisplayHdrPaperWhite"},
             {228, &INx2Vi2Session::CancelClientBuffer, "CancelClientBuffer"},
             {229, &INx2Vi2Session::PresentClientBuffer, "PresentClientBuffer"},
         });
@@ -1759,17 +1760,34 @@ private:
                              static_cast<u32>(AvailableSlots >> 32), 0, 0, 0, 0});
     }
 
+    // nn::vi2::QueryDisplayRefreshRate(display name): u32 refresh rate in Hz, then a bool (a u64
+    // in all). nn::vi::detail::DefaultDisplay::QueryRefreshRate takes only -1, 60 or 120 and fails
+    // on anything else; Minecraft polls it and never draws while it fails. A one-word reply left
+    // the bool to whatever the message buffer held.
+    void QueryDisplayRefreshRate(HLERequestContext& ctx) {
+        TipcReplyWords(ctx, {60, 0});
+    }
+
+    // nn::vi2::QueryDisplayHdrPaperWhite(display name): u16 paper white in nits. The empty reply
+    // left it to the message buffer's leftovers; answer the BT.2408 reference white.
+    void QueryDisplayHdrPaperWhite(HLERequestContext& ctx) {
+        TipcReplyWords(ctx, {203});
+    }
+
+    // nn::vi2::QueryDisplayHdrStatus(display name): u64 HdrOutputFormat, u16. The sdk's
+    // DefaultDisplay::QueryHdrStatus takes format 1 as HDR output and fails with 0x272 on
+    // anything above 1. With the empty auto stub reply it read the request's leftover words as
+    // the format; Kirby Air Riders re-queries whenever its HDR status event fires and rebuilt its
+    // window images every few frames, which showed black. Report SDR output.
+    void QueryDisplayHdrStatus(HLERequestContext& ctx) {
+        TipcReplyWords(ctx, {0, 0, 0});
+    }
+
     void ReturnOne(HLERequestContext& ctx) {
         LOG_WARNING(Service, "(STUBBED) nx2:vi2 TIPC {}, returning 1", ctx.GetCommand());
         TipcReplyWords(ctx, {1});
     }
 
-    // The same reply as the auto stub (success, no data), without its log lines.
-    void SucceedQuietly(HLERequestContext& ctx) {
-        IPC::ResponseBuilder rb{ctx, 2};
-        rb.Push(ResultSuccess);
-    }
-
     // Must be < 8; nn::vi::detail::LayerHistory creates 7 timestamp recorders per layer.
     void GetTimestampRecorderCount(HLERequestContext& ctx) {
         LOG_WARNING(Service, "(STUBBED) nx2:vi2 TIPC 5, returning 7");
-- 
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