From 625f4db47d0e6f899654e055320ec9fef5f8618f Mon Sep 17 00:00:00 2001
From: Swung0x48 <swung0x48@outlook.com>
Date: Tue, 29 Sep 2026 04:29:49 -0400
Subject: [PATCH] [Feat] (MG_Remote, P10 A): a present reports the fences
 finished so far before it returns the credit, so the client the credit
 releases finds the fence of a frame ago already known

---
 MobileGL/MG_Remote/Server/PipeApplier.cpp   | 5 +++++
 MobileGL/MG_Remote/Server/ServerSession.cpp | 5 +++++
 MobileGL/MG_Remote/Server/ServerSession.h   | 3 +++
 3 files changed, 13 insertions(+)

diff --git a/MobileGL/MG_Remote/Server/PipeApplier.cpp b/MobileGL/MG_Remote/Server/PipeApplier.cpp
index 5e5bf9a1..9513c49c 100644
--- a/MobileGL/MG_Remote/Server/PipeApplier.cpp
+++ b/MobileGL/MG_Remote/Server/PipeApplier.cpp
@@ -425,6 +425,11 @@ namespace MobileGL::MG_Remote::Server {
         // swap and not the record's apply. It advances presentAckSerial AND rings the client's
         // bell - a client parked in WaitForPresentAck(kWaitForever) needs the pair.
         if (ServerSession* session = ServerSession::Active()) {
+            // P10 (CONTRACT-P10.md §1): the fences finished by now are reported BEFORE the credit
+            // goes back - a client released by the credit polls or waits on the fence of a frame
+            // or two ago at once, and a report posted only after this batch would race it. A
+            // status query, no submit: the swap has just submitted.
+            if (session->EventRingHasRoom()) ReportSignaledFences(/*flush=*/false);
             session->ReturnPresentCredit(m_lastPresentSerial);
         }
         return true;
diff --git a/MobileGL/MG_Remote/Server/ServerSession.cpp b/MobileGL/MG_Remote/Server/ServerSession.cpp
index 1326c795..15a6488b 100644
--- a/MobileGL/MG_Remote/Server/ServerSession.cpp
+++ b/MobileGL/MG_Remote/Server/ServerSession.cpp
@@ -1144,6 +1144,11 @@ namespace MobileGL::MG_Remote::Server {
         PublishEvents();
     }
 
+    Bool ServerSession::EventRingHasRoom() const {
+        if (!m_accepted || m_link == nullptr) return false;
+        return m_link->Signals().EventRingFull->load(std::memory_order_acquire) == 0;
+    }
+
     // PH-6 (ID-P7-2). THE FIRST DROP, AND THE LATCH IT RAISES.
     //
     // Logged ONCE, by name, with everything a triage needs: which event, how big, what the
diff --git a/MobileGL/MG_Remote/Server/ServerSession.h b/MobileGL/MG_Remote/Server/ServerSession.h
index 9f66e09b..efdae1e4 100644
--- a/MobileGL/MG_Remote/Server/ServerSession.h
+++ b/MobileGL/MG_Remote/Server/ServerSession.h
@@ -214,6 +214,9 @@ namespace MobileGL::MG_Remote::Server {
         // found signaled. Posted and published at once - a client may be polling on it right now.
         // Dropped with the same loud line as PostGlError before Accept.
         void PostFenceSignaled(MG_Pipe::MGPipeHandle fence);
+        // True when SEG_EVENT is not latched full: an optional post (a fence report) goes
+        // there without parking the apply thread. False before Accept.
+        Bool EventRingHasRoom() const;
         Transport::ITransport* Control_Plane();
 
         // ---- PH-6 (ID-P7-2): THE REVERSE CHANNEL IS FORFEITED, NOT FATAL -------------------