1 files changed, 48 insertions, 3 deletions

diff --git a/src/window.c b/src/window.c
index 37266261c74..493e2889537 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1313,6 +1313,7 @@ window_loop (type, obj, mini, frames)
 DEFUN ("get-lru-window", Fget_lru_window, Sget_lru_window, 0, 1, 0,
   "Return the window least recently selected or used for display.\n\
 If optional argument FRAME is `visible', search all visible frames.\n\
+If FRAME is 0, search all visible and iconified frames.\n\
 If FRAME is t, search all frames.\n\
 If FRAME is nil, search only the selected frame.\n\
 If FRAME is a frame, search only that frame.")
@@ -1331,6 +1332,7 @@ If FRAME is a frame, search only that frame.")
 DEFUN ("get-largest-window", Fget_largest_window, Sget_largest_window, 0, 1, 0,
   "Return the largest window in area.\n\
 If optional argument FRAME is `visible', search all visible frames.\n\
+If FRAME is 0, search all visible and iconified frames.\n\
 If FRAME is t, search all frames.\n\
 If FRAME is nil, search only the selected frame.\n\
 If FRAME is a frame, search only that frame.")
@@ -1806,6 +1808,9 @@ Returns the window displaying BUFFER.")
   if (pop_up_windows
 #ifdef MULTI_FRAME
       || FRAME_MINIBUF_ONLY_P (selected_frame)
+      /* If the current frame is a special display frame,
+         don't try to reuse its windows.  */
+      || !NILP (XWINDOW (FRAME_ROOT_WINDOW (selected_frame))->dedicated)
 #endif
       )
     {
@@ -1820,8 +1825,27 @@ Returns the window displaying BUFFER.")
       if (split_height_threshold < window_min_height << 1)
         split_height_threshold = window_min_height << 1;
 
-      window = Fget_largest_window (frames);
+      /* Note that both Fget_largest_window and Fget_lru_window
+         ignore minibuffers and dedicated windows.
+         This means they can return nil.  */
 
+      /* If the frame we would try to split cannot be split,
+         try other frames.  */
+      if (FRAME_NO_SPLIT_P (NILP (frames) ? selected_frame
+                            : last_nonminibuf_frame))
+        {
+          /* Try visible frames first.  */
+          window = Fget_largest_window (Qvisible);
+          /* If that didn't work, try iconified frames.  */
+          if (NILP (window))
+            window = Fget_largest_window (make_number (0));
+          if (NILP (window))
+            window = Fget_largest_window (Qt);
+        }
+      else
+        window = Fget_largest_window (frames);
+
+      /* If we got a tall enough full-width window, split it.  */
       if (!NILP (window)
           && window_height (window) >= split_height_threshold
           && (XFASTINT (XWINDOW (window)->width)
@@ -1830,10 +1854,31 @@ Returns the window displaying BUFFER.")
       else
         {
           window = Fget_lru_window (frames);
-          if ((EQ (window, selected_window)
-               || EQ (XWINDOW (window)->parent, Qnil))
+          /* If the LRU window is selected, and big enough, split it.  */
+          if (!NILP (window)
+              && (EQ (window, selected_window)
+                  || EQ (XWINDOW (window)->parent, Qnil))
               && window_height (window) >= window_min_height << 1)
             window = Fsplit_window (window, Qnil, Qnil);
+#ifdef MULTI_FRAME
+          /* If Fget_lru_window returned nil, try other approaches.  */
+          /* Try visible frames first.  */
+          if (NILP (window))
+            window = Fget_largest_window (Qvisible);
+          /* If that didn't work, try iconified frames.  */
+          if (NILP (window))
+            window = Fget_largest_window (make_number (0));
+          /* Try invisible frames.  */
+          if (NILP (window))
+            window = Fget_largest_window (Qt);
+          /* As a last resort, make a new frame.  */
+          if (NILP (window))
+            window = Fframe_selected_window (call0 (Vpop_up_frame_function));
+#else
+          /* As a last resort, use a non minibuffer window.  */
+          if (NILP (window))
+            window = Fframe_first_window (Fselected_frame ());
+#endif
         }
     }
   else