From 984676299135bdab590acfaa00067902b319ecfb Mon Sep 17 00:00:00 2001
From: Geoffrey McRae <geoff@hostfission.com>
Date: Mon, 13 Jan 2020 19:17:09 +1100
Subject: [PATCH] [all] align the frame data to the page boundary

---
 VERSION                       | 2 +-
 c-host/src/app.c              | 6 +++++-
 client/src/main.c             | 2 +-
 common/include/common/KVMFR.h | 1 +
 obs/lg.c                      | 2 +-
 5 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/VERSION b/VERSION
index 486a2539..2fde6818 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-B1-92-g0d29527758+1
\ No newline at end of file
+B1-94-g17df1ebc6b+1
\ No newline at end of file
diff --git a/c-host/src/app.c b/c-host/src/app.c
index b1b5a208..2147792f 100644
--- a/c-host/src/app.c
+++ b/c-host/src/app.c
@@ -109,6 +109,7 @@ static int frameThread(void * opaque)
   bool         repeatFrame    = false;
   int          frameIndex     = 0;
   CaptureFrame frame          = { 0 };
+  const long   pageSize       = sysinfo_getPageSize();
 
   (void)frameIndex;
   (void)repeatFrame;
@@ -182,9 +183,12 @@ static int frameThread(void * opaque)
     fi->height  = frame.height;
     fi->stride  = frame.stride;
     fi->pitch   = frame.pitch;
+    fi->offset  = pageSize - sizeof(FrameBuffer);
     frameValid  = true;
 
-    FrameBuffer fb = (FrameBuffer)(fi + 1);
+    // put the framebuffer on the border of the next page
+    // this is to allow for aligned DMA transfers by the receiver
+    FrameBuffer fb = (FrameBuffer)(((uint8_t*)fi) + fi->offset);
     framebuffer_prepare(fb);
 
     /* we post and then get the frame, this is intentional! */
diff --git a/client/src/main.c b/client/src/main.c
index e97bce0f..e3afe4c3 100644
--- a/client/src/main.c
+++ b/client/src/main.c
@@ -440,7 +440,7 @@ static int frameThread(void * unused)
       updatePositionInfo();
     }
 
-    FrameBuffer fb = (FrameBuffer)(frame + 1);
+    FrameBuffer fb = (FrameBuffer)(((uint8_t*)frame) + frame->offset);
     if (!state.lgr->on_frame_event(state.lgrData, lgrFormat, fb))
     {
       DEBUG_ERROR("renderer on frame event returned failure");
diff --git a/common/include/common/KVMFR.h b/common/include/common/KVMFR.h
index 3b39420a..f01064c3 100644
--- a/common/include/common/KVMFR.h
+++ b/common/include/common/KVMFR.h
@@ -60,5 +60,6 @@ typedef struct KVMFRFrame
   uint32_t    height;      // the height
   uint32_t    stride;      // the row stride (zero if compressed data)
   uint32_t    pitch;       // the row pitch  (stride in bytes or the compressed frame size)
+  uint32_t    offset;      // offset from the start of this header to the FrameBuffer header
 }
 KVMFRFrame;
\ No newline at end of file
diff --git a/obs/lg.c b/obs/lg.c
index f541fd30..edd87068 100644
--- a/obs/lg.c
+++ b/obs/lg.c
@@ -164,7 +164,7 @@ static void lgVideoTick(void * data, float seconds)
     }
   }
 
-  FrameBuffer fb = (FrameBuffer)(frame + 1);
+  FrameBuffer fb = (FrameBuffer)(((uint8_t*)frame) + frame->offset);
 
   uint8_t *texData;
   uint32_t linesize;