Index: libs/ardour/ardour/lv2_plugin.h
===================================================================
--- libs/ardour/ardour/lv2_plugin.h	(revision 5710)
+++ libs/ardour/ardour/lv2_plugin.h	(working copy)
@@ -161,6 +161,7 @@
 	SLV2Value srate;
 	SLV2Value gtk_gui;
 	SLV2Value external_gui;
+	SLV2Value logarithmic;
 };
 
 
Index: gtk2_ardour/lv2_external_ui.h
===================================================================
--- gtk2_ardour/lv2_external_ui.h	(revision 0)
+++ gtk2_ardour/lv2_external_ui.h	(revision 0)
@@ -0,0 +1,101 @@
+/* -*- Mode: C ; c-basic-offset: 2 -*- */
+/*****************************************************************************
+ *
+ *  This work is in public domain.
+ *
+ *  This file is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ *  If you have questions, contact Nedko Arnaudov <nedko@arnaudov.name> or
+ *  ask in #lad channel, FreeNode IRC network.
+ *
+ *****************************************************************************/
+
+#ifndef LV2_EXTERNAL_UI_H__5AFE09A5_0FB7_47AF_924E_2AF0F8DE8873__INCLUDED
+#define LV2_EXTERNAL_UI_H__5AFE09A5_0FB7_47AF_924E_2AF0F8DE8873__INCLUDED
+
+/** UI extension suitable for out-of-process UIs */
+#define LV2_EXTERNAL_UI_URI "http://lv2plug.in/ns/extensions/ui#external"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+#if 0
+} /* Adjust editor indent */
+#endif
+
+/**
+ * When LV2_EXTERNAL_UI_URI UI is instantiated, the returned
+ * LV2UI_Widget handle must be cast to pointer to struct lv2_external_ui.
+ * UI is created in invisible state.
+ */
+struct lv2_external_ui
+{
+  /**
+   * Host calls this function regulary. UI library implementing the
+   * callback may do IPC or redraw the UI.
+   *
+   * @param _this_ the UI context
+   */
+  void (* run)(struct lv2_external_ui * _this_);
+
+  /**
+   * Host calls this function to make the plugin UI visible.
+   *
+   * @param _this_ the UI context
+   */
+  void (* show)(struct lv2_external_ui * _this_);
+
+  /**
+   * Host calls this function to make the plugin UI invisible again.
+   *
+   * @param _this_ the UI context
+   */
+  void (* hide)(struct lv2_external_ui * _this_);
+};
+
+#define LV2_EXTERNAL_UI_RUN(ptr) (ptr)->run(ptr)
+#define LV2_EXTERNAL_UI_SHOW(ptr) (ptr)->show(ptr)
+#define LV2_EXTERNAL_UI_HIDE(ptr) (ptr)->hide(ptr)
+
+/**
+ * On UI instantiation, host must supply LV2_EXTERNAL_UI_URI
+ * feature. LV2_Feature::data must be pointer to struct lv2_external_ui_host. */
+struct lv2_external_ui_host
+{
+  /**
+   * Callback that plugin UI will call
+   * when UI (GUI window) is closed by user.
+   * This callback wil; be called during execution of lv2_external_ui::run()
+   * (i.e. not from background thread).
+   *
+   * After this callback is called, UI is defunct. Host must call
+   * LV2UI_Descriptor::cleanup(). If host wants to make the UI visible
+   * again UI must be reinstantiated.
+   *
+   * @param controller Host context associated with plugin UI, as
+   * supplied to LV2UI_Descriptor::instantiate()
+   */
+  void (* ui_closed)(LV2UI_Controller controller);
+
+  /**
+   * Optional (may be NULL) "user friendly" identifier which the UI
+   * may display to allow a user to easily associate this particular
+   * UI instance with the correct plugin instance as it is represented
+   * by the host (e.g. "track 1" or "channel 4").
+   *
+   * If supplied by host, the string will be referenced only during
+   * LV2UI_Descriptor::instantiate()
+   */
+  const char * plugin_human_id;
+};
+
+#if 0
+{ /* Adjust editor indent */
+#endif
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* #ifndef LV2_EXTERNAL_UI_H__5AFE09A5_0FB7_47AF_924E_2AF0F8DE8873__INCLUDED */