Simplify Framebuffer::Session interface

This patch removes the 'Framebuffer::Session::release()' function from
the interface to make the mode-change protocol consistent with the way
the Rom_session interface handles ROM-module changes. That is, the
client acknowledges the release of its current dataspace by requesting a
new dataspace via the 'Framebuffer::Session::dataspace()' function.

Fixes #1057

demo/src/server/liquid_framebuffer/services.cc

@@ -287,8 +287,6 @@ namespace Framebuffer
 				return _window_content.fb_ds_cap();
 			}
 
-			void release() { }
-
 			Mode mode() const
 			{
 				return Mode(_window_content.mode_size().w(),

libports/src/app/qt5/qt_avplay/framebuffer_session_component.cc

@@ -64,12 +64,6 @@ namespace Framebuffer {
 	}
 
 
-	void Session_component::release()
-	{
-		_framebuffer.release();
-	}
-
-
 	Mode Session_component::mode() const
 	{
 		return _framebuffer.mode();

libports/src/app/qt5/qt_avplay/framebuffer_session_component.h

@@ -46,7 +46,6 @@ namespace Framebuffer {
 			                  int max_height = 0);
 
 			Genode::Dataspace_capability dataspace();
-			void release();
 			Mode mode() const;
 			void mode_sigh(Genode::Signal_context_capability sigh_cap);
 			void refresh(int x, int y, int w, int h);

libports/src/lib/qt5/qtbase/src/plugins/platforms/nitpicker/window_slave_policy.h

@@ -99,8 +99,6 @@ class Window_slave_policy : public Genode::Slave_policy
 			if (_framebuffer)
 				Genode::env()->rm_session()->detach(_framebuffer);
 
-			session_client.release();
-
 			Dataspace_capability framebuffer_ds = session_client.dataspace();
 			if (framebuffer_ds.valid()) {
 				_framebuffer = Genode::env()->rm_session()->attach(framebuffer_ds);

os/include/framebuffer_session/client.h

@@ -27,8 +27,6 @@ namespace Framebuffer {
 		Genode::Dataspace_capability dataspace() {
 			return call<Rpc_dataspace>(); }
 
-		void release() { call<Rpc_release>(); }
-
 		Mode mode() const { return call<Rpc_mode>(); }
 
 		void mode_sigh(Genode::Signal_context_capability sigh) {

os/include/framebuffer_session/framebuffer_session.h

@@ -70,21 +70,18 @@ namespace Framebuffer {
 
 		/**
 		 * Request dataspace representing the logical frame buffer
+		 *
+		 * By calling this function, the framebuffer client enables the server
+		 * to reallocate the framebuffer dataspace (e.g., on mode changes).
+		 * Hence, prior calling this function, the client should make sure to
+		 * have detached the previously requested dataspace from its local
+		 * address space.
 		 */
 		virtual Genode::Dataspace_capability dataspace() = 0;
 
 		/**
-		 * Release framebuffer, free dataspace
+		 * Request display-mode properties of the framebuffer ready to be
-		 *
+		 * obtained via the 'dataspace()' function
-		 * By calling this function, the framebuffer client enables the server
-		 * to reallocate the framebuffer dataspace on mode changes. Prior
-		 * calling this function, the client should have detached the dataspace
-		 * from its local address space.
-		 */
-		virtual void release() = 0;
-
-		/**
-		 * Request current display-mode properties
 		 */
 		virtual Mode mode() const = 0;
 
@@ -95,11 +92,9 @@ namespace Framebuffer {
 		 * fly. For example, a virtual framebuffer presented in a window may
 		 * get resized according to the window dimensions. By installing a
 		 * signal handler for mode changes, the framebuffer client can respond
-		 * to such changes. From the client's perspective, the original mode
+		 * to such changes. The new mode can be obtained using the 'mode()'
-		 * stays in effect until the client calls 'release()'. After having
+		 * function. However, from the client's perspective, the original mode
-		 * released the framebuffer, the new mode can be obtained using the
+		 * stays in effect until the it calls 'dataspace()' again.
-		 * 'mode()' function and a new framebuffer dataspace can be requested
-		 * by calling 'dataspace()'.
 		 */
 		virtual void mode_sigh(Genode::Signal_context_capability sigh) = 0;
 
@@ -116,13 +111,11 @@ namespace Framebuffer {
 		 *********************/
 
 		GENODE_RPC(Rpc_dataspace, Genode::Dataspace_capability, dataspace);
-		GENODE_RPC(Rpc_release, void, release);
 		GENODE_RPC(Rpc_mode, Mode, mode);
 		GENODE_RPC(Rpc_refresh, void, refresh, int, int, int, int);
 		GENODE_RPC(Rpc_mode_sigh, void, mode_sigh, Genode::Signal_context_capability);
 
-		GENODE_RPC_INTERFACE(Rpc_dataspace, Rpc_release, Rpc_mode,
+		GENODE_RPC_INTERFACE(Rpc_dataspace, Rpc_mode, Rpc_mode_sigh, Rpc_refresh);
-		                     Rpc_mode_sigh, Rpc_refresh);
 	};
 }
 

os/include/platform/imx53/imx_framebuffer_session/client.h

@@ -28,8 +28,6 @@ namespace Framebuffer {
 		Genode::Dataspace_capability dataspace() {
 			return call<Rpc_dataspace>(); }
 
-		void release() { call<Rpc_release>(); }
-
 		Mode mode() const { return call<Rpc_mode>(); }
 
 		void mode_sigh(Genode::Signal_context_capability sigh) {

os/src/drivers/framebuffer/exynos5/main.cc

@@ -90,8 +90,6 @@ class Framebuffer::Session_component
 
 		Dataspace_capability dataspace() { return _ds; }
 
-		void release() { }
-
 		Mode mode() const
 		{
 			return Mode(_width, _height, _convert_format(_format));

os/src/drivers/framebuffer/imx53/main.cc

@@ -69,7 +69,6 @@ class Framebuffer::Session_component :
 		 **************************************/
 
 		Dataspace_capability dataspace() { return _buffered ? _bb_ds : _fb_ds; }
-		void release()                   { }
 		Mode mode() const                { return _mode; }
 		void mode_sigh(Genode::Signal_context_capability) { }
 

os/src/drivers/framebuffer/omap4/main.cc

@@ -77,8 +77,6 @@ class Framebuffer::Session_component : public Genode::Rpc_object<Framebuffer::Se
 
 		Dataspace_capability dataspace() { return _ds; }
 
-		void release() { }
-
 		Mode mode() const
 		{
 			return Mode(_width,

os/src/drivers/framebuffer/pl11x/main.cc

@@ -157,8 +157,6 @@ namespace Framebuffer
 
 			Genode::Dataspace_capability dataspace() { return _fb_ds_cap; }
 
-			void release() { }
-
 			Mode mode() const { return Mode(SCR_WIDTH, SCR_HEIGHT, Mode::RGB565); }
 
 			void mode_sigh(Genode::Signal_context_capability) { }

os/src/drivers/framebuffer/rpi/main.cc

@@ -47,8 +47,6 @@ class Framebuffer::Session_component : public Genode::Rpc_object<Framebuffer::Se
 
 		Dataspace_capability dataspace() { return _fb_mem.cap(); }
 
-		void release() { }
-
 		Mode mode() const
 		{
 			return Mode(_width, _height, Mode::RGB565);

os/src/drivers/framebuffer/sdl/fb_sdl.cc

@@ -61,8 +61,6 @@ namespace Framebuffer {
 
 			Genode::Dataspace_capability dataspace() { return fb_ds_cap; }
 
-			void release() { }
-
 			Mode mode() const { return _mode; }
 
 			void mode_sigh(Genode::Signal_context_capability) { }

os/src/server/nitpicker/main.cc

@@ -369,8 +369,6 @@ class Framebuffer::Session_component : public Genode::Rpc_object<Session>
 			return _buffer ? _buffer->ds_cap() : Genode::Ram_dataspace_capability();
 		}
 
-		void release() { }
-
 		Mode mode() const
 		{
 			return _mode;

qt4/src/app/qt_avplay/framebuffer_session_component.cc

@@ -64,12 +64,6 @@ namespace Framebuffer {
 	}
 
 
-	void Session_component::release()
-	{
-		_framebuffer.release();
-	}
-
-
 	Mode Session_component::mode() const
 	{
 		return _framebuffer.mode();

qt4/src/app/qt_avplay/framebuffer_session_component.h

@@ -46,7 +46,6 @@ namespace Framebuffer {
 			                  int max_height = 0);
 
 			Genode::Dataspace_capability dataspace();
-			void release();
 			Mode mode() const;
 			void mode_sigh(Genode::Signal_context_capability sigh_cap);
 			void refresh(int x, int y, int w, int h);