diff --git a/gdb/cli/cli-interp.c b/gdb/cli/cli-interp.c
index bd50af7..f994d47 100644
--- a/gdb/cli/cli-interp.c
+++ b/gdb/cli/cli-interp.c
@@ -33,8 +33,13 @@ struct cli_interp
   struct ui_out *cli_uiout;
 };
 
-/* The interpreter for the console interpreter.  */
-static struct interp *cli_interp;
+static struct cli_interp *
+as_cli_interp (struct interp *interp)
+{
+  if (strcmp (interp_name (interp), INTERP_CONSOLE) == 0)
+    return (struct cli_interp *) interp_data (interp);
+  return NULL;
+}
 
 /* Longjmp-safe wrapper for "execute_command".  */
 static struct gdb_exception safe_execute_command (struct ui_out *uiout,
@@ -50,10 +55,17 @@ static struct gdb_exception safe_execute_command (struct ui_out *uiout,
 static void
 cli_on_normal_stop (struct bpstats *bs, int print_frame)
 {
-  if (!interp_quiet_p (cli_interp))
+  struct switch_thru_all_uis state;
+
+  SWITCH_THRU_ALL_UIS (state)
     {
+      struct cli_interp *cli = as_cli_interp (top_level_interpreter ());
+
+      if (cli == NULL)
+	continue;
+
       if (print_frame)
-	print_stop_event (interp_ui_out (cli_interp));
+	print_stop_event (cli->cli_uiout);
     }
 }
 
@@ -62,8 +74,17 @@ cli_on_normal_stop (struct bpstats *bs, int print_frame)
 static void
 cli_on_signal_received (enum gdb_signal siggnal)
 {
-  if (!interp_quiet_p (cli_interp))
-    print_signal_received_reason (interp_ui_out (cli_interp), siggnal);
+  struct switch_thru_all_uis state;
+
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct cli_interp *cli = as_cli_interp (top_level_interpreter ());
+
+      if (cli == NULL)
+	continue;
+
+      print_signal_received_reason (cli->cli_uiout, siggnal);
+    }
 }
 
 /* Observer for the end_stepping_range notification.  */
@@ -71,8 +92,17 @@ cli_on_signal_received (enum gdb_signal siggnal)
 static void
 cli_on_end_stepping_range (void)
 {
-  if (!interp_quiet_p (cli_interp))
-    print_end_stepping_range_reason (interp_ui_out (cli_interp));
+  struct switch_thru_all_uis state;
+
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct cli_interp *cli = as_cli_interp (top_level_interpreter ());
+
+      if (cli == NULL)
+	continue;
+
+      print_end_stepping_range_reason (cli->cli_uiout);
+    }
 }
 
 /* Observer for the signalled notification.  */
@@ -80,8 +110,17 @@ cli_on_end_stepping_range (void)
 static void
 cli_on_signal_exited (enum gdb_signal siggnal)
 {
-  if (!interp_quiet_p (cli_interp))
-    print_signal_exited_reason (interp_ui_out (cli_interp), siggnal);
+  struct switch_thru_all_uis state;
+
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct cli_interp *cli = as_cli_interp (top_level_interpreter ());
+
+      if (cli == NULL)
+	continue;
+
+      print_signal_exited_reason (cli->cli_uiout, siggnal);
+    }
 }
 
 /* Observer for the exited notification.  */
@@ -89,8 +128,17 @@ cli_on_signal_exited (enum gdb_signal siggnal)
 static void
 cli_on_exited (int exitstatus)
 {
-  if (!interp_quiet_p (cli_interp))
-    print_exited_reason (interp_ui_out (cli_interp), exitstatus);
+  struct switch_thru_all_uis state;
+
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct cli_interp *cli = as_cli_interp (top_level_interpreter ());
+
+      if (cli == NULL)
+	continue;
+
+      print_exited_reason (cli->cli_uiout, exitstatus);
+    }
 }
 
 /* Observer for the no_history notification.  */
@@ -98,8 +146,17 @@ cli_on_exited (int exitstatus)
 static void
 cli_on_no_history (void)
 {
-  if (!interp_quiet_p (cli_interp))
-    print_no_history_reason (interp_ui_out (cli_interp));
+  struct switch_thru_all_uis state;
+
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct cli_interp *cli = as_cli_interp (top_level_interpreter ());
+
+      if (cli == NULL)
+	continue;
+
+      print_no_history_reason (cli->cli_uiout);
+    }
 }
 
 /* Observer for the sync_execution_done notification.  */
@@ -107,8 +164,12 @@ cli_on_no_history (void)
 static void
 cli_on_sync_execution_done (void)
 {
-  if (!interp_quiet_p (cli_interp))
-    display_gdb_prompt (NULL);
+  struct cli_interp *cli = as_cli_interp (top_level_interpreter ());
+
+  if (cli == NULL)
+    return;
+
+  display_gdb_prompt (NULL);
 }
 
 /* Observer for the command_error notification.  */
@@ -116,8 +177,17 @@ cli_on_sync_execution_done (void)
 static void
 cli_on_command_error (void)
 {
-  if (!interp_quiet_p (cli_interp))
-    display_gdb_prompt (NULL);
+  struct switch_thru_all_uis state;
+
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct cli_interp *cli = as_cli_interp (top_level_interpreter ());
+
+      if (cli == NULL)
+	continue;
+
+      display_gdb_prompt (NULL);
+    }
 }
 
 /* These implement the cli out interpreter: */
@@ -125,19 +195,6 @@ cli_on_command_error (void)
 static void *
 cli_interpreter_init (struct interp *self, int top_level)
 {
-  if (top_level)
-    cli_interp = self;
-
-  /* If changing this, remember to update tui-interp.c as well.  */
-  observer_attach_normal_stop (cli_on_normal_stop);
-  observer_attach_end_stepping_range (cli_on_end_stepping_range);
-  observer_attach_signal_received (cli_on_signal_received);
-  observer_attach_signal_exited (cli_on_signal_exited);
-  observer_attach_exited (cli_on_exited);
-  observer_attach_no_history (cli_on_no_history);
-  observer_attach_sync_execution_done (cli_on_sync_execution_done);
-  observer_attach_command_error (cli_on_command_error);
-
   return interp_data (self);
 }
 
@@ -265,4 +322,14 @@ void
 _initialize_cli_interp (void)
 {
   interp_factory_register (INTERP_CONSOLE, cli_interp_factory);
+
+  /* If changing this, remember to update tui-interp.c as well.  */
+  observer_attach_normal_stop (cli_on_normal_stop);
+  observer_attach_end_stepping_range (cli_on_end_stepping_range);
+  observer_attach_signal_received (cli_on_signal_received);
+  observer_attach_signal_exited (cli_on_signal_exited);
+  observer_attach_exited (cli_on_exited);
+  observer_attach_no_history (cli_on_no_history);
+  observer_attach_sync_execution_done (cli_on_sync_execution_done);
+  observer_attach_command_error (cli_on_command_error);
 }
diff --git a/gdb/event-top.c b/gdb/event-top.c
index 736a77a..3dc95ab 100644
--- a/gdb/event-top.c
+++ b/gdb/event-top.c
@@ -356,8 +356,44 @@ top_level_prompt (void)
   return xstrdup (prompt);
 }
 
-static struct ui current_ui_;
-struct ui *current_ui = &current_ui_;
+static struct ui main_ui_;
+
+struct ui *current_ui = &main_ui_;
+struct ui *ui_list = &main_ui_;
+
+static void
+restore_ui_cleanup (void *data)
+{
+  current_ui = (struct ui *) data;
+}
+
+void
+switch_thru_all_uis_init (struct switch_thru_all_uis *state)
+{
+  state->iter = ui_list;
+  state->old_chain = make_cleanup (restore_ui_cleanup, current_ui);
+}
+
+int
+switch_thru_all_uis_cond (struct switch_thru_all_uis *state)
+{
+  if (state->iter != NULL)
+    {
+      current_ui = state->iter;
+      return 1;
+    }
+  else
+    {
+      do_cleanups (state->old_chain);
+      return 0;
+    }
+}
+
+void
+switch_thru_all_uis_next (struct switch_thru_all_uis *state)
+{
+  state->iter = state->iter->next;
+}
 
 /* Get a pointer to the current UI's line builder.  */
 
diff --git a/gdb/mi/mi-interp.c b/gdb/mi/mi-interp.c
index 9e6f5e4..872c201 100644
--- a/gdb/mi/mi-interp.c
+++ b/gdb/mi/mi-interp.c
@@ -88,6 +88,14 @@ static void mi_on_sync_execution_done (void);
 
 static int report_initial_inferior (struct inferior *inf, void *closure);
 
+static struct mi_interp *
+as_mi_interp (struct interp *interp)
+{
+  if (ui_out_is_mi_like_p (interp_ui_out (interp)))
+    return (struct mi_interp *) interp_data (interp);
+  return NULL;
+}
+
 static void *
 mi_interpreter_init (struct interp *interp, int top_level)
 {
@@ -127,39 +135,8 @@ mi_interpreter_init (struct interp *interp, int top_level)
   mi->mi_uiout = mi_out_new (mi_version);
   mi->cli_uiout = cli_out_new (mi->out);
 
-  /* There are installed even if MI is not the top level interpreter.
-     The callbacks themselves decide whether to be skipped.  */
-  observer_attach_signal_received (mi_on_signal_received);
-  observer_attach_end_stepping_range (mi_on_end_stepping_range);
-  observer_attach_signal_exited (mi_on_signal_exited);
-  observer_attach_exited (mi_on_exited);
-  observer_attach_no_history (mi_on_no_history);
-
   if (top_level)
     {
-      observer_attach_new_thread (mi_new_thread);
-      observer_attach_thread_exit (mi_thread_exit);
-      observer_attach_inferior_added (mi_inferior_added);
-      observer_attach_inferior_appeared (mi_inferior_appeared);
-      observer_attach_inferior_exit (mi_inferior_exit);
-      observer_attach_inferior_removed (mi_inferior_removed);
-      observer_attach_record_changed (mi_record_changed);
-      observer_attach_normal_stop (mi_on_normal_stop);
-      observer_attach_target_resumed (mi_on_resume);
-      observer_attach_solib_loaded (mi_solib_loaded);
-      observer_attach_solib_unloaded (mi_solib_unloaded);
-      observer_attach_about_to_proceed (mi_about_to_proceed);
-      observer_attach_traceframe_changed (mi_traceframe_changed);
-      observer_attach_tsv_created (mi_tsv_created);
-      observer_attach_tsv_deleted (mi_tsv_deleted);
-      observer_attach_tsv_modified (mi_tsv_modified);
-      observer_attach_breakpoint_created (mi_breakpoint_created);
-      observer_attach_breakpoint_deleted (mi_breakpoint_deleted);
-      observer_attach_breakpoint_modified (mi_breakpoint_modified);
-      observer_attach_command_param_changed (mi_command_param_changed);
-      observer_attach_memory_changed (mi_memory_changed);
-      observer_attach_sync_execution_done (mi_on_sync_execution_done);
-
       /* The initial inferior is created before this function is
 	 called, so we need to report it explicitly.  Use iteration in
 	 case future version of GDB creates more than one inferior
@@ -311,6 +288,12 @@ mi_execute_command_wrapper (const char *cmd)
 static void
 mi_on_sync_execution_done (void)
 {
+  struct ui *ui = current_ui;
+  struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
+
+  if (mi == NULL)
+    return;
+
   /* If MI is sync, then output the MI prompt now, indicating we're
      ready for further input.  */
   if (!mi_async_p ())
@@ -356,38 +339,47 @@ mi_command_loop (void *data)
 static void
 mi_new_thread (struct thread_info *t)
 {
-  struct mi_interp *mi = (struct mi_interp *) top_level_interpreter_data ();
-  struct inferior *inf = find_inferior_ptid (t->ptid);
+  struct switch_thru_all_uis state;
 
-  gdb_assert (inf);
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
 
-  fprintf_unfiltered (mi->event_channel, 
-		      "thread-created,id=\"%d\",group-id=\"i%d\"",
-		      t->global_num, inf->num);
-  gdb_flush (mi->event_channel);
+      if (mi == NULL)
+	continue;
+
+      fprintf_unfiltered (mi->event_channel,
+			  "thread-created,id=\"%d\",group-id=\"i%d\"",
+			  t->global_num, t->inf->num);
+      gdb_flush (mi->event_channel);
+    }
 }
 
 static void
 mi_thread_exit (struct thread_info *t, int silent)
 {
-  struct mi_interp *mi;
-  struct inferior *inf;
-  struct cleanup *old_chain;
+  struct switch_thru_all_uis state;
 
   if (silent)
     return;
 
-  inf = find_inferior_ptid (t->ptid);
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
+      struct cleanup *old_chain;
 
-  mi = (struct mi_interp *) top_level_interpreter_data ();
-  old_chain = make_cleanup_restore_target_terminal ();
-  target_terminal_ours ();
-  fprintf_unfiltered (mi->event_channel, 
-		      "thread-exited,id=\"%d\",group-id=\"i%d\"",
-		      t->global_num, inf->num);
-  gdb_flush (mi->event_channel);
+      if (mi == NULL)
+	continue;
 
-  do_cleanups (old_chain);
+      old_chain = make_cleanup_restore_target_terminal ();
+      target_terminal_ours ();
+      fprintf_unfiltered (mi->event_channel,
+			  "thread-exited,id=\"%d\",group-id=\"i%d\"",
+			  t->global_num, t->inf->num);
+      gdb_flush (mi->event_channel);
+
+      do_cleanups (old_chain);
+    }
 }
 
 /* Emit notification on changing the state of record.  */
@@ -395,97 +387,132 @@ mi_thread_exit (struct thread_info *t, int silent)
 static void
 mi_record_changed (struct inferior *inferior, int started)
 {
-  struct mi_interp *mi = (struct mi_interp *) top_level_interpreter_data ();
+  struct switch_thru_all_uis state;
 
-  fprintf_unfiltered (mi->event_channel,  "record-%s,thread-group=\"i%d\"",
-		      started ? "started" : "stopped", inferior->num);
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
 
-  gdb_flush (mi->event_channel);
+      if (mi == NULL)
+	continue;
+
+      fprintf_unfiltered (mi->event_channel,  "record-%s,thread-group=\"i%d\"",
+			  started ? "started" : "stopped", inferior->num);
+
+      gdb_flush (mi->event_channel);
+    }
 }
 
 static void
 mi_inferior_added (struct inferior *inf)
 {
-  struct mi_interp *mi = (struct mi_interp *) top_level_interpreter_data ();
+  struct switch_thru_all_uis state;
 
-  target_terminal_ours ();
-  fprintf_unfiltered (mi->event_channel,
-		      "thread-group-added,id=\"i%d\"",
-		      inf->num);
-  gdb_flush (mi->event_channel);
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct interp *interp;
+      struct mi_interp *mi;
+
+      /* We'll be called once for the initial inferior, before the top
+	 level interpreter is set.  */
+      interp = top_level_interpreter ();
+      if (interp == NULL)
+	continue;
+
+      mi = as_mi_interp (interp);
+      if (mi == NULL)
+	continue;
+
+      target_terminal_ours ();
+      fprintf_unfiltered (mi->event_channel,
+			  "thread-group-added,id=\"i%d\"",
+			  inf->num);
+      gdb_flush (mi->event_channel);
+    }
 }
 
 static void
 mi_inferior_appeared (struct inferior *inf)
 {
-  struct mi_interp *mi = (struct mi_interp *) top_level_interpreter_data ();
+  struct switch_thru_all_uis state;
 
-  target_terminal_ours ();
-  fprintf_unfiltered (mi->event_channel,
-		      "thread-group-started,id=\"i%d\",pid=\"%d\"",
-		      inf->num, inf->pid);
-  gdb_flush (mi->event_channel);
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
+
+      if (mi == NULL)
+	continue;
+
+      target_terminal_ours ();
+      fprintf_unfiltered (mi->event_channel,
+			  "thread-group-started,id=\"i%d\",pid=\"%d\"",
+			  inf->num, inf->pid);
+      gdb_flush (mi->event_channel);
+    }
 }
 
 static void
 mi_inferior_exit (struct inferior *inf)
 {
-  struct mi_interp *mi = (struct mi_interp *) top_level_interpreter_data ();
+  struct switch_thru_all_uis state;
 
-  target_terminal_ours ();
-  if (inf->has_exit_code)
-    fprintf_unfiltered (mi->event_channel,
-			"thread-group-exited,id=\"i%d\",exit-code=\"%s\"",
-			inf->num, int_string (inf->exit_code, 8, 0, 0, 1));
-  else
-    fprintf_unfiltered (mi->event_channel,
-			"thread-group-exited,id=\"i%d\"", inf->num);
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
 
-  gdb_flush (mi->event_channel);  
+      if (mi == NULL)
+	continue;
+
+      target_terminal_ours ();
+      if (inf->has_exit_code)
+	fprintf_unfiltered (mi->event_channel,
+			    "thread-group-exited,id=\"i%d\",exit-code=\"%s\"",
+			    inf->num, int_string (inf->exit_code, 8, 0, 0, 1));
+      else
+	fprintf_unfiltered (mi->event_channel,
+			    "thread-group-exited,id=\"i%d\"", inf->num);
+
+      gdb_flush (mi->event_channel);
+    }
 }
 
 static void
 mi_inferior_removed (struct inferior *inf)
 {
-  struct mi_interp *mi = (struct mi_interp *) top_level_interpreter_data ();
+  struct switch_thru_all_uis state;
 
-  target_terminal_ours ();
-  fprintf_unfiltered (mi->event_channel,
-		      "thread-group-removed,id=\"i%d\"",
-		      inf->num);
-  gdb_flush (mi->event_channel);
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
+
+      if (mi == NULL)
+	continue;
+
+      target_terminal_ours ();
+      fprintf_unfiltered (mi->event_channel,
+			  "thread-group-removed,id=\"i%d\"",
+			  inf->num);
+      gdb_flush (mi->event_channel);
+    }
 }
 
 /* Return the MI interpreter, if it is active -- either because it's
    the top-level interpreter or the interpreter executing the current
    command.  Returns NULL if the MI interpreter is not being used.  */
 
-static struct interp *
-find_mi_interpreter (void)
+static struct mi_interp *
+find_mi_interp (void)
 {
-  struct interp *interp;
-
-  interp = top_level_interpreter ();
-  if (ui_out_is_mi_like_p (interp_ui_out (interp)))
-    return interp;
-
-  interp = command_interp ();
-  if (ui_out_is_mi_like_p (interp_ui_out (interp)))
-    return interp;
-
-  return NULL;
-}
+  struct mi_interp *mi;
 
-/* Return the MI_INTERP structure of the active MI interpreter.
-   Returns NULL if MI is not active.  */
+  mi = as_mi_interp (top_level_interpreter ());
+  if (mi != NULL)
+    return mi;
 
-static struct mi_interp *
-mi_interp_data (void)
-{
-  struct interp *interp = find_mi_interpreter ();
+  mi = as_mi_interp (command_interp ());
+  if (mi != NULL)
+    return mi;
 
-  if (interp != NULL)
-    return (struct mi_interp *) interp_data (interp);
   return NULL;
 }
 
@@ -498,13 +525,18 @@ mi_interp_data (void)
 static void
 mi_on_signal_received (enum gdb_signal siggnal)
 {
-  struct mi_interp *mi = mi_interp_data ();
+  struct switch_thru_all_uis state;
 
-  if (mi == NULL)
-    return;
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = find_mi_interp ();
+
+      if (mi == NULL)
+	continue;
 
-  print_signal_received_reason (mi->mi_uiout, siggnal);
-  print_signal_received_reason (mi->cli_uiout, siggnal);
+      print_signal_received_reason (mi->mi_uiout, siggnal);
+      print_signal_received_reason (mi->cli_uiout, siggnal);
+    }
 }
 
 /* Observer for the end_stepping_range notification.  */
@@ -512,13 +544,18 @@ mi_on_signal_received (enum gdb_signal siggnal)
 static void
 mi_on_end_stepping_range (void)
 {
-  struct mi_interp *mi = mi_interp_data ();
+  struct switch_thru_all_uis state;
 
-  if (mi == NULL)
-    return;
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = find_mi_interp ();
 
-  print_end_stepping_range_reason (mi->mi_uiout);
-  print_end_stepping_range_reason (mi->cli_uiout);
+      if (mi == NULL)
+	continue;
+
+      print_end_stepping_range_reason (mi->mi_uiout);
+      print_end_stepping_range_reason (mi->cli_uiout);
+    }
 }
 
 /* Observer for the signal_exited notification.  */
@@ -526,13 +563,18 @@ mi_on_end_stepping_range (void)
 static void
 mi_on_signal_exited (enum gdb_signal siggnal)
 {
-  struct mi_interp *mi = mi_interp_data ();
+  struct switch_thru_all_uis state;
 
-  if (mi == NULL)
-    return;
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = find_mi_interp ();
+
+      if (mi == NULL)
+	continue;
 
-  print_signal_exited_reason (mi->mi_uiout, siggnal);
-  print_signal_exited_reason (mi->cli_uiout, siggnal);
+      print_signal_exited_reason (mi->mi_uiout, siggnal);
+      print_signal_exited_reason (mi->cli_uiout, siggnal);
+    }
 }
 
 /* Observer for the exited notification.  */
@@ -540,13 +582,18 @@ mi_on_signal_exited (enum gdb_signal siggnal)
 static void
 mi_on_exited (int exitstatus)
 {
-  struct mi_interp *mi = mi_interp_data ();
+  struct switch_thru_all_uis state;
 
-  if (mi == NULL)
-    return;
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = find_mi_interp ();
 
-  print_exited_reason (mi->mi_uiout, exitstatus);
-  print_exited_reason (mi->cli_uiout, exitstatus);
+      if (mi == NULL)
+	continue;
+
+      print_exited_reason (mi->mi_uiout, exitstatus);
+      print_exited_reason (mi->cli_uiout, exitstatus);
+    }
 }
 
 /* Observer for the no_history notification.  */
@@ -554,17 +601,22 @@ mi_on_exited (int exitstatus)
 static void
 mi_on_no_history (void)
 {
-  struct mi_interp *mi = mi_interp_data ();
+  struct switch_thru_all_uis state;
 
-  if (mi == NULL)
-    return;
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = find_mi_interp ();
 
-  print_no_history_reason (mi->mi_uiout);
-  print_no_history_reason (mi->cli_uiout);
+      if (mi == NULL)
+	continue;
+
+      print_no_history_reason (mi->mi_uiout);
+      print_no_history_reason (mi->cli_uiout);
+    }
 }
 
 static void
-mi_on_normal_stop (struct bpstats *bs, int print_frame)
+mi_on_normal_stop_1 (struct bpstats *bs, int print_frame)
 {
   /* Since this can be called when CLI command is executing,
      using cli interpreter, be sure to use MI uiout for output,
@@ -645,6 +697,20 @@ mi_on_normal_stop (struct bpstats *bs, int print_frame)
 }
 
 static void
+mi_on_normal_stop (struct bpstats *bs, int print_frame)
+{
+  struct switch_thru_all_uis state;
+
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      if (as_mi_interp (top_level_interpreter ()) == NULL)
+	continue;
+
+      mi_on_normal_stop_1 (bs, print_frame);
+    }
+}
+
+static void
 mi_about_to_proceed (void)
 {
   /* Suppress output while calling an inferior function.  */
@@ -675,21 +741,29 @@ struct mi_suppress_notification mi_suppress_notification =
 static void
 mi_traceframe_changed (int tfnum, int tpnum)
 {
-  struct mi_interp *mi = (struct mi_interp *) top_level_interpreter_data ();
+  struct switch_thru_all_uis state;
 
   if (mi_suppress_notification.traceframe)
     return;
 
-  target_terminal_ours ();
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
 
-  if (tfnum >= 0)
-    fprintf_unfiltered (mi->event_channel, "traceframe-changed,"
-			"num=\"%d\",tracepoint=\"%d\"\n",
-			tfnum, tpnum);
-  else
-    fprintf_unfiltered (mi->event_channel, "traceframe-changed,end");
+      if (mi == NULL)
+	continue;
 
-  gdb_flush (mi->event_channel);
+      target_terminal_ours ();
+
+      if (tfnum >= 0)
+	fprintf_unfiltered (mi->event_channel, "traceframe-changed,"
+			    "num=\"%d\",tracepoint=\"%d\"\n",
+			    tfnum, tpnum);
+      else
+	fprintf_unfiltered (mi->event_channel, "traceframe-changed,end");
+
+      gdb_flush (mi->event_channel);
+    }
 }
 
 /* Emit notification on creating a trace state variable.  */
@@ -697,15 +771,23 @@ mi_traceframe_changed (int tfnum, int tpnum)
 static void
 mi_tsv_created (const struct trace_state_variable *tsv)
 {
-  struct mi_interp *mi = (struct mi_interp *) top_level_interpreter_data ();
+  struct switch_thru_all_uis state;
 
-  target_terminal_ours ();
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
 
-  fprintf_unfiltered (mi->event_channel, "tsv-created,"
-		      "name=\"%s\",initial=\"%s\"\n",
-		      tsv->name, plongest (tsv->initial_value));
+      if (mi == NULL)
+	continue;
 
-  gdb_flush (mi->event_channel);
+      target_terminal_ours ();
+
+      fprintf_unfiltered (mi->event_channel, "tsv-created,"
+			  "name=\"%s\",initial=\"%s\"\n",
+			  tsv->name, plongest (tsv->initial_value));
+
+      gdb_flush (mi->event_channel);
+    }
 }
 
 /* Emit notification on deleting a trace state variable.  */
@@ -713,17 +795,25 @@ mi_tsv_created (const struct trace_state_variable *tsv)
 static void
 mi_tsv_deleted (const struct trace_state_variable *tsv)
 {
-  struct mi_interp *mi = (struct mi_interp *) top_level_interpreter_data ();
+  struct switch_thru_all_uis state;
 
-  target_terminal_ours ();
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
 
-  if (tsv != NULL)
-    fprintf_unfiltered (mi->event_channel, "tsv-deleted,"
-			"name=\"%s\"\n", tsv->name);
-  else
-    fprintf_unfiltered (mi->event_channel, "tsv-deleted\n");
+      if (mi == NULL)
+	continue;
 
-  gdb_flush (mi->event_channel);
+      target_terminal_ours ();
+
+      if (tsv != NULL)
+	fprintf_unfiltered (mi->event_channel, "tsv-deleted,"
+			    "name=\"%s\"\n", tsv->name);
+      else
+	fprintf_unfiltered (mi->event_channel, "tsv-deleted\n");
+
+      gdb_flush (mi->event_channel);
+    }
 }
 
 /* Emit notification on modifying a trace state variable.  */
@@ -731,25 +821,35 @@ mi_tsv_deleted (const struct trace_state_variable *tsv)
 static void
 mi_tsv_modified (const struct trace_state_variable *tsv)
 {
-  struct mi_interp *mi = (struct mi_interp *) top_level_interpreter_data ();
-  struct ui_out *mi_uiout = interp_ui_out (top_level_interpreter ());
+  struct switch_thru_all_uis state;
 
-  target_terminal_ours ();
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
+      struct ui_out *mi_uiout;
 
-  fprintf_unfiltered (mi->event_channel,
-		      "tsv-modified");
+      if (mi == NULL)
+	continue;
 
-  ui_out_redirect (mi_uiout, mi->event_channel);
+      mi_uiout = interp_ui_out (top_level_interpreter ());
 
-  ui_out_field_string (mi_uiout, "name", tsv->name);
-  ui_out_field_string (mi_uiout, "initial",
-		       plongest (tsv->initial_value));
-  if (tsv->value_known)
-    ui_out_field_string (mi_uiout, "current", plongest (tsv->value));
+      target_terminal_ours ();
 
-  ui_out_redirect (mi_uiout, NULL);
+      fprintf_unfiltered (mi->event_channel,
+			  "tsv-modified");
 
-  gdb_flush (mi->event_channel);
+      ui_out_redirect (mi_uiout, mi->event_channel);
+
+      ui_out_field_string (mi_uiout, "name", tsv->name);
+      ui_out_field_string (mi_uiout, "initial",
+			   plongest (tsv->initial_value));
+      if (tsv->value_known)
+	ui_out_field_string (mi_uiout, "current", plongest (tsv->value));
+
+      ui_out_redirect (mi_uiout, NULL);
+
+      gdb_flush (mi->event_channel);
+    }
 }
 
 /* Emit notification about a created breakpoint.  */
@@ -757,8 +857,7 @@ mi_tsv_modified (const struct trace_state_variable *tsv)
 static void
 mi_breakpoint_created (struct breakpoint *b)
 {
-  struct mi_interp *mi = (struct mi_interp *) top_level_interpreter_data ();
-  struct ui_out *mi_uiout = interp_ui_out (top_level_interpreter ());
+  struct switch_thru_all_uis state;
 
   if (mi_suppress_notification.breakpoint)
     return;
@@ -766,29 +865,40 @@ mi_breakpoint_created (struct breakpoint *b)
   if (b->number <= 0)
     return;
 
-  target_terminal_ours ();
-  fprintf_unfiltered (mi->event_channel,
-		      "breakpoint-created");
-  /* We want the output from gdb_breakpoint_query to go to
-     mi->event_channel.  One approach would be to just call
-     gdb_breakpoint_query, and then use mi_out_put to send the current
-     content of mi_outout into mi->event_channel.  However, that will
-     break if anything is output to mi_uiout prior to calling the
-     breakpoint_created notifications.  So, we use
-     ui_out_redirect.  */
-  ui_out_redirect (mi_uiout, mi->event_channel);
-  TRY
+  SWITCH_THRU_ALL_UIS (state)
     {
-      gdb_breakpoint_query (mi_uiout, b->number, NULL);
-    }
-  CATCH (e, RETURN_MASK_ERROR)
-    {
-    }
-  END_CATCH
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
+      struct ui_out *mi_uiout;
+
+      if (mi == NULL)
+	continue;
+
+      mi_uiout = interp_ui_out (top_level_interpreter ());
+
+      target_terminal_ours ();
+      fprintf_unfiltered (mi->event_channel,
+			  "breakpoint-created");
+      /* We want the output from gdb_breakpoint_query to go to
+	 mi->event_channel.  One approach would be to just call
+	 gdb_breakpoint_query, and then use mi_out_put to send the current
+	 content of mi_outout into mi->event_channel.  However, that will
+	 break if anything is output to mi_uiout prior to calling the
+	 breakpoint_created notifications.  So, we use
+	 ui_out_redirect.  */
+      ui_out_redirect (mi_uiout, mi->event_channel);
+      TRY
+	{
+	  gdb_breakpoint_query (mi_uiout, b->number, NULL);
+	}
+      CATCH (e, RETURN_MASK_ERROR)
+	{
+	}
+      END_CATCH
 
-  ui_out_redirect (mi_uiout, NULL);
+	ui_out_redirect (mi_uiout, NULL);
 
-  gdb_flush (mi->event_channel);
+      gdb_flush (mi->event_channel);
+    }
 }
 
 /* Emit notification about deleted breakpoint.  */
@@ -796,7 +906,7 @@ mi_breakpoint_created (struct breakpoint *b)
 static void
 mi_breakpoint_deleted (struct breakpoint *b)
 {
-  struct mi_interp *mi = (struct mi_interp *) top_level_interpreter_data ();
+  struct switch_thru_all_uis state;
 
   if (mi_suppress_notification.breakpoint)
     return;
@@ -804,12 +914,20 @@ mi_breakpoint_deleted (struct breakpoint *b)
   if (b->number <= 0)
     return;
 
-  target_terminal_ours ();
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
 
-  fprintf_unfiltered (mi->event_channel, "breakpoint-deleted,id=\"%d\"",
-		      b->number);
+      if (mi == NULL)
+	continue;
 
-  gdb_flush (mi->event_channel);
+      target_terminal_ours ();
+
+      fprintf_unfiltered (mi->event_channel, "breakpoint-deleted,id=\"%d\"",
+			  b->number);
+
+      gdb_flush (mi->event_channel);
+    }
 }
 
 /* Emit notification about modified breakpoint.  */
@@ -817,8 +935,7 @@ mi_breakpoint_deleted (struct breakpoint *b)
 static void
 mi_breakpoint_modified (struct breakpoint *b)
 {
-  struct mi_interp *mi = (struct mi_interp *) top_level_interpreter_data ();
-  struct ui_out *mi_uiout = interp_ui_out (top_level_interpreter ());
+  struct switch_thru_all_uis state;
 
   if (mi_suppress_notification.breakpoint)
     return;
@@ -826,40 +943,57 @@ mi_breakpoint_modified (struct breakpoint *b)
   if (b->number <= 0)
     return;
 
-  target_terminal_ours ();
-  fprintf_unfiltered (mi->event_channel,
-		      "breakpoint-modified");
-  /* We want the output from gdb_breakpoint_query to go to
-     mi->event_channel.  One approach would be to just call
-     gdb_breakpoint_query, and then use mi_out_put to send the current
-     content of mi_outout into mi->event_channel.  However, that will
-     break if anything is output to mi_uiout prior to calling the
-     breakpoint_created notifications.  So, we use
-     ui_out_redirect.  */
-  ui_out_redirect (mi_uiout, mi->event_channel);
-  TRY
-    {
-      gdb_breakpoint_query (mi_uiout, b->number, NULL);
-    }
-  CATCH (e, RETURN_MASK_ERROR)
+  SWITCH_THRU_ALL_UIS (state)
     {
-    }
-  END_CATCH
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
+
+      if (mi == NULL)
+	continue;
+
+      target_terminal_ours ();
+      fprintf_unfiltered (mi->event_channel,
+			  "breakpoint-modified");
+      /* We want the output from gdb_breakpoint_query to go to
+	 mi->event_channel.  One approach would be to just call
+	 gdb_breakpoint_query, and then use mi_out_put to send the current
+	 content of mi_outout into mi->event_channel.  However, that will
+	 break if anything is output to mi_uiout prior to calling the
+	 breakpoint_created notifications.  So, we use
+	 ui_out_redirect.  */
+      ui_out_redirect (mi->mi_uiout, mi->event_channel);
+      TRY
+	{
+	  gdb_breakpoint_query (mi->mi_uiout, b->number, NULL);
+	}
+      CATCH (e, RETURN_MASK_ERROR)
+	{
+	}
+      END_CATCH
 
-  ui_out_redirect (mi_uiout, NULL);
+      ui_out_redirect (mi->mi_uiout, NULL);
 
-  gdb_flush (mi->event_channel);
+      gdb_flush (mi->event_channel);
+    }
 }
 
 static int
 mi_output_running_pid (struct thread_info *info, void *arg)
 {
   ptid_t *ptid = (ptid_t *) arg;
+  struct switch_thru_all_uis state;
+
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
+
+      if (mi == NULL)
+	continue;
 
-  if (ptid_get_pid (*ptid) == ptid_get_pid (info->ptid))
-    fprintf_unfiltered (raw_stdout,
-			"*running,thread-id=\"%d\"\n",
-			info->global_num);
+      if (ptid_get_pid (*ptid) == ptid_get_pid (info->ptid))
+	fprintf_unfiltered (raw_stdout,
+			    "*running,thread-id=\"%d\"\n",
+			    info->global_num);
+    }
 
   return 0;
 }
@@ -877,19 +1011,8 @@ mi_inferior_count (struct inferior *inf, void *arg)
 }
 
 static void
-mi_on_resume (ptid_t ptid)
+mi_on_resume_1 (ptid_t ptid)
 {
-  struct thread_info *tp = NULL;
-
-  if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
-    tp = inferior_thread ();
-  else
-    tp = find_thread_ptid (ptid);
-
-  /* Suppress output while calling an inferior function.  */
-  if (tp->control.in_infcall)
-    return;
-
   /* To cater for older frontends, emit ^running, but do it only once
      per each command.  We do it here, since at this point we know
      that the target was successfully resumed, and in non-async mode,
@@ -944,54 +1067,102 @@ mi_on_resume (ptid_t ptid)
 }
 
 static void
-mi_solib_loaded (struct so_list *solib)
+mi_on_resume (ptid_t ptid)
 {
-  struct mi_interp *mi = (struct mi_interp *) top_level_interpreter_data ();
-  struct ui_out *uiout = interp_ui_out (top_level_interpreter ());
-
-  target_terminal_ours ();
+  struct thread_info *tp = NULL;
+  struct switch_thru_all_uis state;
 
-  fprintf_unfiltered (mi->event_channel, "library-loaded");
+  if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
+    tp = inferior_thread ();
+  else
+    tp = find_thread_ptid (ptid);
 
-  ui_out_redirect (uiout, mi->event_channel);
+  /* Suppress output while calling an inferior function.  */
+  if (tp->control.in_infcall)
+    return;
 
-  ui_out_field_string (uiout, "id", solib->so_original_name);
-  ui_out_field_string (uiout, "target-name", solib->so_original_name);
-  ui_out_field_string (uiout, "host-name", solib->so_name);
-  ui_out_field_int (uiout, "symbols-loaded", solib->symbols_loaded);
-  if (!gdbarch_has_global_solist (target_gdbarch ()))
+  SWITCH_THRU_ALL_UIS (state)
     {
-      ui_out_field_fmt (uiout, "thread-group", "i%d", current_inferior ()->num);
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
+
+      if (mi == NULL)
+	continue;
+
+      mi_on_resume_1 (ptid);
     }
+}
 
-  ui_out_redirect (uiout, NULL);
+static void
+mi_solib_loaded (struct so_list *solib)
+{
+  struct switch_thru_all_uis state;
 
-  gdb_flush (mi->event_channel);
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
+      struct ui_out *uiout;
+
+      if (mi == NULL)
+	continue;
+
+      uiout = interp_ui_out (top_level_interpreter ());
+
+      target_terminal_ours ();
+
+      fprintf_unfiltered (mi->event_channel, "library-loaded");
+
+      ui_out_redirect (uiout, mi->event_channel);
+
+      ui_out_field_string (uiout, "id", solib->so_original_name);
+      ui_out_field_string (uiout, "target-name", solib->so_original_name);
+      ui_out_field_string (uiout, "host-name", solib->so_name);
+      ui_out_field_int (uiout, "symbols-loaded", solib->symbols_loaded);
+      if (!gdbarch_has_global_solist (target_gdbarch ()))
+	{
+	  ui_out_field_fmt (uiout, "thread-group", "i%d",
+			    current_inferior ()->num);
+	}
+
+      ui_out_redirect (uiout, NULL);
+
+      gdb_flush (mi->event_channel);
+    }
 }
 
 static void
 mi_solib_unloaded (struct so_list *solib)
 {
-  struct mi_interp *mi = (struct mi_interp *) top_level_interpreter_data ();
-  struct ui_out *uiout = interp_ui_out (top_level_interpreter ());
+  struct switch_thru_all_uis state;
 
-  target_terminal_ours ();
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
+      struct ui_out *uiout;
 
-  fprintf_unfiltered (mi->event_channel, "library-unloaded");
+      if (mi == NULL)
+	continue;
 
-  ui_out_redirect (uiout, mi->event_channel);
+      uiout = interp_ui_out (top_level_interpreter ());
 
-  ui_out_field_string (uiout, "id", solib->so_original_name);
-  ui_out_field_string (uiout, "target-name", solib->so_original_name);
-  ui_out_field_string (uiout, "host-name", solib->so_name);
-  if (!gdbarch_has_global_solist (target_gdbarch ()))
-    {
-      ui_out_field_fmt (uiout, "thread-group", "i%d", current_inferior ()->num);
-    }
+      target_terminal_ours ();
 
-  ui_out_redirect (uiout, NULL);
+      fprintf_unfiltered (mi->event_channel, "library-unloaded");
 
-  gdb_flush (mi->event_channel);
+      ui_out_redirect (uiout, mi->event_channel);
+
+      ui_out_field_string (uiout, "id", solib->so_original_name);
+      ui_out_field_string (uiout, "target-name", solib->so_original_name);
+      ui_out_field_string (uiout, "host-name", solib->so_name);
+      if (!gdbarch_has_global_solist (target_gdbarch ()))
+	{
+	  ui_out_field_fmt (uiout, "thread-group", "i%d",
+			    current_inferior ()->num);
+	}
+
+      ui_out_redirect (uiout, NULL);
+
+      gdb_flush (mi->event_channel);
+    }
 }
 
 /* Emit notification about the command parameter change.  */
@@ -999,25 +1170,34 @@ mi_solib_unloaded (struct so_list *solib)
 static void
 mi_command_param_changed (const char *param, const char *value)
 {
-  struct mi_interp *mi = (struct mi_interp *) top_level_interpreter_data ();
-  struct ui_out *mi_uiout = interp_ui_out (top_level_interpreter ());
+  struct switch_thru_all_uis state;
 
   if (mi_suppress_notification.cmd_param_changed)
     return;
 
-  target_terminal_ours ();
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
+      struct ui_out *mi_uiout;
 
-  fprintf_unfiltered (mi->event_channel,
-		      "cmd-param-changed");
+      if (mi == NULL)
+	continue;
 
-  ui_out_redirect (mi_uiout, mi->event_channel);
+      mi_uiout = interp_ui_out (top_level_interpreter ());
 
-  ui_out_field_string (mi_uiout, "param", param);
-  ui_out_field_string (mi_uiout, "value", value);
+      target_terminal_ours ();
 
-  ui_out_redirect (mi_uiout, NULL);
+      fprintf_unfiltered (mi->event_channel, "cmd-param-changed");
 
-  gdb_flush (mi->event_channel);
+      ui_out_redirect (mi_uiout, mi->event_channel);
+
+      ui_out_field_string (mi_uiout, "param", param);
+      ui_out_field_string (mi_uiout, "value", value);
+
+      ui_out_redirect (mi_uiout, NULL);
+
+      gdb_flush (mi->event_channel);
+    }
 }
 
 /* Emit notification about the target memory change.  */
@@ -1026,45 +1206,54 @@ static void
 mi_memory_changed (struct inferior *inferior, CORE_ADDR memaddr,
 		   ssize_t len, const bfd_byte *myaddr)
 {
-  struct mi_interp *mi = (struct mi_interp *) top_level_interpreter_data ();
-  struct ui_out *mi_uiout = interp_ui_out (top_level_interpreter ());
-  struct obj_section *sec;
+  struct switch_thru_all_uis state;
 
   if (mi_suppress_notification.memory)
     return;
 
-  target_terminal_ours ();
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct mi_interp *mi = as_mi_interp (top_level_interpreter ());
+      struct ui_out *mi_uiout;
+      struct obj_section *sec;
 
-  fprintf_unfiltered (mi->event_channel,
-		      "memory-changed");
+      if (mi == NULL)
+	continue;
 
-  ui_out_redirect (mi_uiout, mi->event_channel);
+      mi_uiout = interp_ui_out (top_level_interpreter ());
 
-  ui_out_field_fmt (mi_uiout, "thread-group", "i%d", inferior->num);
-  ui_out_field_core_addr (mi_uiout, "addr", target_gdbarch (), memaddr);
-  ui_out_field_fmt (mi_uiout, "len", "%s", hex_string (len));
+      target_terminal_ours ();
 
-  /* Append 'type=code' into notification if MEMADDR falls in the range of
-     sections contain code.  */
-  sec = find_pc_section (memaddr);
-  if (sec != NULL && sec->objfile != NULL)
-    {
-      flagword flags = bfd_get_section_flags (sec->objfile->obfd,
-					      sec->the_bfd_section);
+      fprintf_unfiltered (mi->event_channel, "memory-changed");
 
-      if (flags & SEC_CODE)
-	ui_out_field_string (mi_uiout, "type", "code");
-    }
+      ui_out_redirect (mi_uiout, mi->event_channel);
 
-  ui_out_redirect (mi_uiout, NULL);
+      ui_out_field_fmt (mi_uiout, "thread-group", "i%d", inferior->num);
+      ui_out_field_core_addr (mi_uiout, "addr", target_gdbarch (), memaddr);
+      ui_out_field_fmt (mi_uiout, "len", "%s", hex_string (len));
 
-  gdb_flush (mi->event_channel);
+      /* Append 'type=code' into notification if MEMADDR falls in the range of
+	 sections contain code.  */
+      sec = find_pc_section (memaddr);
+      if (sec != NULL && sec->objfile != NULL)
+	{
+	  flagword flags = bfd_get_section_flags (sec->objfile->obfd,
+						  sec->the_bfd_section);
+
+	  if (flags & SEC_CODE)
+	    ui_out_field_string (mi_uiout, "type", "code");
+	}
+
+      ui_out_redirect (mi_uiout, NULL);
+
+      gdb_flush (mi->event_channel);
+    }
 }
 
 static int
 report_initial_inferior (struct inferior *inf, void *closure)
 {
-  /* This function is called from mi_intepreter_init, and since
+  /* This function is called from mi_interpreter_init, and since
      mi_inferior_added assumes that inferior is fully initialized
      and top_level_interpreter_data is set, we cannot call
      it here.  */
@@ -1161,4 +1350,35 @@ _initialize_mi_interp (void)
   interp_factory_register (INTERP_MI2, mi_interp_factory);
   interp_factory_register (INTERP_MI3, mi_interp_factory);
   interp_factory_register (INTERP_MI, mi_interp_factory);
+
+  /* There are installed even if MI is not the top level interpreter.
+     The callbacks themselves decide whether to be skipped.  */
+  observer_attach_signal_received (mi_on_signal_received);
+  observer_attach_end_stepping_range (mi_on_end_stepping_range);
+  observer_attach_signal_exited (mi_on_signal_exited);
+  observer_attach_exited (mi_on_exited);
+  observer_attach_no_history (mi_on_no_history);
+
+  observer_attach_new_thread (mi_new_thread);
+  observer_attach_thread_exit (mi_thread_exit);
+  observer_attach_inferior_added (mi_inferior_added);
+  observer_attach_inferior_appeared (mi_inferior_appeared);
+  observer_attach_inferior_exit (mi_inferior_exit);
+  observer_attach_inferior_removed (mi_inferior_removed);
+  observer_attach_record_changed (mi_record_changed);
+  observer_attach_normal_stop (mi_on_normal_stop);
+  observer_attach_target_resumed (mi_on_resume);
+  observer_attach_solib_loaded (mi_solib_loaded);
+  observer_attach_solib_unloaded (mi_solib_unloaded);
+  observer_attach_about_to_proceed (mi_about_to_proceed);
+  observer_attach_traceframe_changed (mi_traceframe_changed);
+  observer_attach_tsv_created (mi_tsv_created);
+  observer_attach_tsv_deleted (mi_tsv_deleted);
+  observer_attach_tsv_modified (mi_tsv_modified);
+  observer_attach_breakpoint_created (mi_breakpoint_created);
+  observer_attach_breakpoint_deleted (mi_breakpoint_deleted);
+  observer_attach_breakpoint_modified (mi_breakpoint_modified);
+  observer_attach_command_param_changed (mi_command_param_changed);
+  observer_attach_memory_changed (mi_memory_changed);
+  observer_attach_sync_execution_done (mi_on_sync_execution_done);
 }
diff --git a/gdb/top.h b/gdb/top.h
index 2daa03b..b97be4c 100644
--- a/gdb/top.h
+++ b/gdb/top.h
@@ -36,6 +36,8 @@ struct tl_interp_info;
 
 struct ui
 {
+  struct ui *next;
+
   /* The UI's line builder.  This is to used to accumulate input until
      we have a whole command line.  */
   struct buffer line_builder;
@@ -84,6 +86,24 @@ struct ui
 };
 
 extern struct ui *current_ui;
+extern struct ui *ui_list;
+
+struct switch_thru_all_uis
+{
+  struct ui *iter;
+  struct cleanup *old_chain;
+};
+
+extern void switch_thru_all_uis_init (struct switch_thru_all_uis *state);
+extern int switch_thru_all_uis_cond (struct switch_thru_all_uis *state);
+extern void switch_thru_all_uis_next (struct switch_thru_all_uis *state);
+
+  /* Traverse through all UI, and switch the current UI to the one
+     being iterated.  */
+#define SWITCH_THRU_ALL_UIS(STATE)		\
+  for (switch_thru_all_uis_init (&STATE);		\
+       switch_thru_all_uis_cond (&STATE);		\
+       switch_thru_all_uis_next (&STATE))		\
 
 /* From top.c.  */
 extern char *saved_command_line;
diff --git a/gdb/tui/tui-interp.c b/gdb/tui/tui-interp.c
index c7910bc..fc16f21 100644
--- a/gdb/tui/tui-interp.c
+++ b/gdb/tui/tui-interp.c
@@ -38,8 +38,13 @@ static struct ui_out *tui_ui_out (struct interp *self);
    gdb.  */
 static int tui_start_enabled = 0;
 
-/* The TUI interpreter.  */
-static struct interp *tui_interp;
+static struct interp *
+as_tui_interp (struct interp *interp)
+{
+  if (strcmp (interp_name (interp), INTERP_TUI) == 0)
+    return interp;
+  return NULL;
+}
 
 /* Cleanup the tui before exiting.  */
 
@@ -60,10 +65,17 @@ tui_exit (void)
 static void
 tui_on_normal_stop (struct bpstats *bs, int print_frame)
 {
-  if (!interp_quiet_p (tui_interp))
+  struct switch_thru_all_uis state;
+
+  SWITCH_THRU_ALL_UIS (state)
     {
+      struct interp *tui = as_tui_interp (top_level_interpreter ());
+
+      if (tui == NULL)
+	continue;
+
       if (print_frame)
-	print_stop_event (tui_ui_out (tui_interp));
+	print_stop_event (tui_ui_out (tui));
     }
 }
 
@@ -72,8 +84,17 @@ tui_on_normal_stop (struct bpstats *bs, int print_frame)
 static void
 tui_on_signal_received (enum gdb_signal siggnal)
 {
-  if (!interp_quiet_p (tui_interp))
-    print_signal_received_reason (tui_ui_out (tui_interp), siggnal);
+  struct switch_thru_all_uis state;
+
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct interp *tui = as_tui_interp (top_level_interpreter ());
+
+      if (tui == NULL)
+	continue;
+
+      print_signal_received_reason (tui_ui_out (tui), siggnal);
+    }
 }
 
 /* Observer for the end_stepping_range notification.  */
@@ -81,8 +102,17 @@ tui_on_signal_received (enum gdb_signal siggnal)
 static void
 tui_on_end_stepping_range (void)
 {
-  if (!interp_quiet_p (tui_interp))
-    print_end_stepping_range_reason (tui_ui_out (tui_interp));
+  struct switch_thru_all_uis state;
+
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct interp *tui = as_tui_interp (top_level_interpreter ());
+
+      if (tui == NULL)
+	continue;
+
+      print_end_stepping_range_reason (tui_ui_out (tui));
+    }
 }
 
 /* Observer for the signal_exited notification.  */
@@ -90,8 +120,17 @@ tui_on_end_stepping_range (void)
 static void
 tui_on_signal_exited (enum gdb_signal siggnal)
 {
-  if (!interp_quiet_p (tui_interp))
-    print_signal_exited_reason (tui_ui_out (tui_interp), siggnal);
+  struct switch_thru_all_uis state;
+
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct interp *tui = as_tui_interp (top_level_interpreter ());
+
+      if (tui == NULL)
+	continue;
+
+      print_signal_exited_reason (tui_ui_out (tui), siggnal);
+    }
 }
 
 /* Observer for the exited notification.  */
@@ -99,8 +138,17 @@ tui_on_signal_exited (enum gdb_signal siggnal)
 static void
 tui_on_exited (int exitstatus)
 {
-  if (!interp_quiet_p (tui_interp))
-    print_exited_reason (tui_ui_out (tui_interp), exitstatus);
+  struct switch_thru_all_uis state;
+
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct interp *tui = as_tui_interp (top_level_interpreter ());
+
+      if (tui == NULL)
+	continue;
+
+      print_exited_reason (tui_ui_out (tui), exitstatus);
+    }
 }
 
 /* Observer for the no_history notification.  */
@@ -108,8 +156,17 @@ tui_on_exited (int exitstatus)
 static void
 tui_on_no_history (void)
 {
-  if (!interp_quiet_p (tui_interp))
-    print_no_history_reason (tui_ui_out (tui_interp));
+  struct switch_thru_all_uis state;
+
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct interp *tui = as_tui_interp (top_level_interpreter ());
+
+      if (tui == NULL)
+	continue;
+
+      print_no_history_reason (tui_ui_out (tui));
+    }
 }
 
 /* Observer for the sync_execution_done notification.  */
@@ -117,8 +174,12 @@ tui_on_no_history (void)
 static void
 tui_on_sync_execution_done (void)
 {
-  if (!interp_quiet_p (tui_interp))
-    display_gdb_prompt (NULL);
+  struct interp *tui = as_tui_interp (top_level_interpreter ());
+
+  if (tui == NULL)
+    return;
+
+  display_gdb_prompt (NULL);
 }
 
 /* Observer for the command_error notification.  */
@@ -126,8 +187,17 @@ tui_on_sync_execution_done (void)
 static void
 tui_on_command_error (void)
 {
-  if (!interp_quiet_p (tui_interp))
-    display_gdb_prompt (NULL);
+  struct switch_thru_all_uis state;
+
+  SWITCH_THRU_ALL_UIS (state)
+    {
+      struct interp *tui = as_tui_interp (top_level_interpreter ());
+
+      if (tui == NULL)
+	continue;
+
+      display_gdb_prompt (NULL);
+    }
 }
 
 /* These implement the TUI interpreter.  */
@@ -138,9 +208,6 @@ tui_init (struct interp *self, int top_level)
   /* Install exit handler to leave the screen in a good shape.  */
   atexit (tui_exit);
 
-  if (top_level)
-    tui_interp = self;
-
   tui_initialize_static_data ();
 
   tui_initialize_io ();
@@ -148,16 +215,6 @@ tui_init (struct interp *self, int top_level)
   if (ui_file_isatty (gdb_stdout))
     tui_initialize_readline ();
 
-  /* If changing this, remember to update cli-interp.c as well.  */
-  observer_attach_normal_stop (tui_on_normal_stop);
-  observer_attach_signal_received (tui_on_signal_received);
-  observer_attach_end_stepping_range (tui_on_end_stepping_range);
-  observer_attach_signal_exited (tui_on_signal_exited);
-  observer_attach_exited (tui_on_exited);
-  observer_attach_no_history (tui_on_no_history);
-  observer_attach_sync_execution_done (tui_on_sync_execution_done);
-  observer_attach_command_error (tui_on_command_error);
-
   return NULL;
 }
 
@@ -242,4 +299,14 @@ _initialize_tui_interp (void)
       xfree (interpreter_p);
       interpreter_p = xstrdup (INTERP_TUI);
     }
+
+  /* If changing this, remember to update cli-interp.c as well.  */
+  observer_attach_normal_stop (tui_on_normal_stop);
+  observer_attach_signal_received (tui_on_signal_received);
+  observer_attach_end_stepping_range (tui_on_end_stepping_range);
+  observer_attach_signal_exited (tui_on_signal_exited);
+  observer_attach_exited (tui_on_exited);
+  observer_attach_no_history (tui_on_no_history);
+  observer_attach_sync_execution_done (tui_on_sync_execution_done);
+  observer_attach_command_error (tui_on_command_error);
 }
