From 14317feebd73b9f459d77574a92d2a20ffb01222 Mon Sep 17 00:00:00 2001
From: Gabe Rudy <rudy@goldenhelix.com>
Date: Sun, 3 May 2026 07:24:00 -0600
Subject: [PATCH] Flush pending pseudo-encodings in writeLosslessRefresh under
 video mode
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When `video_mode_available` is true, `writeLosslessRefresh()` early-returns
without emitting an FBU. That's correct for the lossless-refresh data path
(video mode owns the pixel stream), but it also drops any pending
pseudo-encoding rects: cursor shape, cursor position, LED state.

The downstream effect: cursor SHAPE updates (e.g. xfwm4 swapping in the
N-S-resize cursor as the pointer approaches a window edge) sit in
`needSetCursor` until some other framebuffer activity triggers a fresh
FBU. On an idle desktop the cursor stays whatever it was last drawn as,
even after seconds of pointer movement.

Trace into `VNCSConnectionST::writeDataUpdate()`:

  if (ui.is_empty() && !writer()->needFakeUpdate() && ...) return;
  ...
  if (!ui.is_empty()) {
      encodeManager.writeUpdate(...);
  } else {
      encodeManager.writeLosslessRefresh(...);   // ← we land here
  }

So when only a pseudo-encoding is pending and there are no pixel changes,
control routes to `writeLosslessRefresh`, which then bails on video mode
without flushing the pseudo-rects.

Fix: before bailing, send a pseudo-only FBU if `needFakeUpdate()` is set.
Uses `pseudoEncodingLastRect` (or counted nRects when the client doesn't
support last-rect) so the message is self-terminating.
---
 common/rfb/EncodeManager.cxx | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/common/rfb/EncodeManager.cxx b/common/rfb/EncodeManager.cxx
index 01cb5a1e1..c3361693f 100644
--- a/common/rfb/EncodeManager.cxx
+++ b/common/rfb/EncodeManager.cxx
@@ -365,8 +365,21 @@ void EncodeManager::writeLosslessRefresh(const Region& req,  const ScreenSet &la
                                          const RenderedCursor* renderedCursor,
                                          size_t maxUpdateSize)
 {
-    if (videoDetected || video_mode_available)
+    if (videoDetected || video_mode_available) {
+        // In video mode there's no lossless refresh to send, but pending
+        // pseudo-encodings (cursor shape, LED state, etc.) must still be
+        // flushed — otherwise the cursor shape lags whenever the desktop
+        // is idle (e.g. user hovering a window edge to resize). Without
+        // this, writeFramebufferUpdate() reaches us via writeDataUpdate's
+        // "ui.is_empty() but needFakeUpdate()" branch and we early-return,
+        // never emitting the FBU that would carry the pseudo-rects.
+        if (conn->writer()->needFakeUpdate()) {
+            int nRects = conn->cp.supportsLastRect ? 0xFFFF : 0;
+            conn->writer()->writeFramebufferUpdateStart(nRects);
+            conn->writer()->writeFramebufferUpdateEnd();
+        }
         return;
+    }
 
     doUpdate(false, getLosslessRefresh(req, maxUpdateSize),
              Region(), Point(), std::vector<CopyPassRect>(), layout, pb, renderedCursor);