From 11b3ac00a89fc2e4bca9da1caacc27f9b15065d0 Mon Sep 17 00:00:00 2001
From: Geoffrey McRae <geoff@hostfission.com>
Date: Wed, 15 Jul 2026 17:10:26 +1000
Subject: [PATCH] [client/obs] update LGMP to detect version missmatch since
 struct change

---
 client/src/main.c |  5 ++++-
 obs/lg.c          | 24 ++++++++++++++++++++----
 repos/LGMP        |  2 +-
 3 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/client/src/main.c b/client/src/main.c
index 94d12ad5..3174f333 100644
--- a/client/src/main.c
+++ b/client/src/main.c
@@ -1438,6 +1438,7 @@ static int lg_run(void)
     core_setGrab(true);
 
   uint32_t udataSize;
+  uint32_t remoteVersion;
   KVMFR *udata;
   int waitCount = 0;
 
@@ -1462,7 +1463,7 @@ restart:
     }
 
     status = lgmpClientSessionInit(g_state.lgmp, &udataSize, (uint8_t **)&udata,
-        NULL);
+        NULL, &remoteVersion);
     switch(status)
     {
       case LGMP_OK:
@@ -1480,6 +1481,8 @@ restart:
             "Please download and install the matching version."
           );
 
+          DEBUG_INFO("LGMP host:%u client:%u",
+              remoteVersion, LGMP_PROTOCOL_VERSION);
           DEBUG_INFO("Waiting for you to upgrade the host application");
         }
 
diff --git a/obs/lg.c b/obs/lg.c
index c73220a8..f4aa3354 100644
--- a/obs/lg.c
+++ b/obs/lg.c
@@ -490,15 +490,31 @@ static void lgUpdate(void * data, obs_data_t * settings)
   uint32_t udataSize;
   KVMFR * udata;
 
-  if (lgmpClientInit(this->shmDev.mem, this->shmDev.size, &this->lgmp)
-      != LGMP_OK)
+  LGMP_STATUS status;
+  if ((status = lgmpClientInit(this->shmDev.mem, this->shmDev.size,
+      &this->lgmp)) != LGMP_OK)
+  {
+    printf("lgmpClientInit: %s\n", lgmpStatusString(status));
     return;
+  }
 
   usleep(200000);
 
-  if (lgmpClientSessionInit(this->lgmp, &udataSize, (uint8_t **)&udata, NULL)
-      != LGMP_OK)
+  uint32_t remoteVersion;
+  if ((status = lgmpClientSessionInit(this->lgmp, &udataSize,
+      (uint8_t **)&udata, NULL, &remoteVersion)) != LGMP_OK)
+  {
+    printf("lgmpClientSessionInit: %s", lgmpStatusString(status));
+    if (status == LGMP_ERR_INVALID_VERSION)
+    {
+      printf("The host application is not compatible with this client\n");
+      printf("Expected LGMP version %u but got %u\n",
+          LGMP_PROTOCOL_VERSION, remoteVersion);
+      printf("This is not a Looking Glass error, do not report this");
+    }
+    printf("\n");
     return;
+  }
 
   if (udataSize < sizeof(KVMFR) ||
       memcmp(udata->magic, KVMFR_MAGIC, sizeof(udata->magic)) != 0 ||
diff --git a/repos/LGMP b/repos/LGMP
index cee29332..149c7310 160000
--- a/repos/LGMP
+++ b/repos/LGMP
@@ -1 +1 @@
-Subproject commit cee29332212b40f54a57cf36e39d301c02c0ce07
+Subproject commit 149c731050d28c93532ee5ab4c84dfe6c2342f49