Support for configuring screen backlight

Accelerant interface:
Introduce new hooks B_SET_BRIGHTNESS and B_GET_BRIGHTNESS. Brightness is
a float in the 0..1 range.

App_server:
Forward brightness things between BScreen and the accelerant.

intel_extreme:
Implement the hooks. Note that this only works for laptop panels, but
the driver will pretend to support it in other cases as well.

Screen preferences:
If the accelerant supports the B_GET_BRIGHTNESS hook, allow to set
brightness with a slider. Otherwise, the slidere is hidden and these
changes aren't visible.

headers/os/add-ons/graphics/Accelerant.h

@@ -52,6 +52,8 @@ enum {
 	B_GET_PREFERRED_DISPLAY_MODE,		/* optional */
 	B_GET_MONITOR_INFO,					/* optional */
 	B_GET_EDID_INFO,					/* optional */
+	B_SET_BRIGHTNESS,                   /* optional */
+	B_GET_BRIGHTNESS,                   /* optional */
 
 	/* cursor managment */
 	B_MOVE_CURSOR = 0x200,				/* optional */
@@ -305,6 +307,9 @@ typedef status_t (*set_dpms_mode)(uint32 dpms_flags);
 typedef status_t (*get_preferred_display_mode)(display_mode* preferredMode);
 typedef status_t (*get_monitor_info)(monitor_info* info);
 typedef status_t (*get_edid_info)(void* info, uint32 size, uint32* _version);
+typedef status_t (*set_brightness)(float brightness);
+typedef status_t (*get_brightness)(float* brightness);
+
 typedef sem_id (*accelerant_retrace_semaphore)(void);
 
 typedef status_t (*set_cursor_shape)(uint16 width, uint16 height,

headers/os/interface/Screen.h

@@ -82,6 +82,9 @@ public:
 			uint32				DPMSState();
 			uint32				DPMSCapabilites();
 
+			status_t			GetBrightness(float*);
+			status_t			SetBrightness(float);
+
 private:
 	// Forbidden and deprecated methods
 								BScreen(const BScreen& other);

headers/private/app/ServerProtocol.h

@@ -174,6 +174,9 @@ enum {
 	AS_GET_DPMS_STATE,
 	AS_GET_DPMS_CAPABILITIES,
 
+	AS_SCREEN_SET_BRIGHTNESS,
+	AS_SCREEN_GET_BRIGHTNESS,
+
 	// Misc stuff
 	AS_GET_ACCELERANT_PATH,
 	AS_GET_DRIVER_PATH,

headers/private/graphics/intel_extreme/intel_extreme.h

@@ -809,6 +809,11 @@ struct intel_free_graphics_memory {
 #define PANEL_DIVISOR_POW_CYCLE_DLY_MASK 0x1f
 #define PANEL_DIVISOR_POW_CYCLE_DLY_SHIFT 0x1f
 
+// Backlight control registers
+#define INTEL_BLC_PWM_CTL2              (0x8250 | REGS_NORTH_SHARED)
+#define INTEL_BLC_PWM_CTL               (0x8254 | REGS_NORTH_SHARED)
+#define INTEL_SBLC_PWM_CTL2             (0x8254 | REGS_SOUTH_SHARED)
+
 // ring buffer commands
 
 #define COMMAND_NOOP					0x00

headers/private/interface/PrivateScreen.h

@@ -82,6 +82,9 @@ public:
 			uint32				DPMSState();
 			uint32				DPMSCapabilites();
 
+			status_t			GetBrightness(float*);
+			status_t			SetBrightness(float);
+
 			void*				BaseAddress();
 			uint32				BytesPerRow();
 

src/add-ons/accelerants/intel_extreme/accelerant_protos.h

@@ -36,6 +36,8 @@ status_t intel_propose_display_mode(display_mode* target,
 status_t intel_set_display_mode(display_mode* mode);
 status_t intel_get_display_mode(display_mode* currentMode);
 status_t intel_get_edid_info(void* info, size_t size, uint32* _version);
+status_t intel_set_brightness(float brightness);
+status_t intel_get_brightness(float* brightness);
 status_t intel_get_frame_buffer_config(frame_buffer_config* config);
 status_t intel_get_pixel_clock_limits(display_mode* mode, uint32* low,
 	uint32* high);

src/add-ons/accelerants/intel_extreme/hooks.cpp

@@ -45,6 +45,10 @@ get_accelerant_hook(uint32 feature, void* data)
 #ifdef __HAIKU__
 		case B_GET_EDID_INFO:
 			return (void*)intel_get_edid_info;
+		case B_SET_BRIGHTNESS:
+			return (void*)intel_set_brightness;
+		case B_GET_BRIGHTNESS:
+			return (void*)intel_get_brightness;
 #endif
 		case B_GET_FRAME_BUFFER_CONFIG:
 			return (void*)intel_get_frame_buffer_config;

src/add-ons/accelerants/intel_extreme/mode.cpp

@@ -659,6 +659,37 @@ intel_get_edid_info(void* info, size_t size, uint32* _version)
 }
 
 
+status_t
+intel_set_brightness(float brightness)
+{
+	CALLED();
+
+	if (brightness < 0 || brightness > 1)
+		return B_BAD_VALUE;
+
+	uint16_t sblc = read32(INTEL_SBLC_PWM_CTL2) >> 16;
+	write32(INTEL_BLC_PWM_CTL, (uint32_t)(sblc * brightness));
+
+	return B_OK;
+}
+
+
+status_t
+intel_get_brightness(float* brightness)
+{
+	CALLED();
+
+	if (brightness == NULL)
+		return B_BAD_VALUE;
+
+	uint16_t sblc = read32(INTEL_SBLC_PWM_CTL2) >> 16;
+	uint16_t  blc = read32( INTEL_BLC_PWM_CTL );
+	*brightness = (float)blc / sblc;
+
+	return B_OK;
+}
+
+
 status_t
 intel_get_frame_buffer_config(frame_buffer_config* config)
 {

src/kits/interface/PrivateScreen.cpp

@@ -678,6 +678,39 @@ BPrivateScreen::DPMSCapabilites()
 }
 
 
+status_t
+BPrivateScreen::GetBrightness(float* brightness)
+{
+	if (brightness == NULL)
+		return B_BAD_VALUE;
+
+	BPrivate::AppServerLink link;
+	link.StartMessage(AS_SCREEN_GET_BRIGHTNESS);
+	link.Attach<int32>(ID());
+
+	status_t status;
+	if (link.FlushWithReply(status) == B_OK && status == B_OK)
+		link.Read<float>(brightness);
+
+	return status;
+}
+
+
+status_t
+BPrivateScreen::SetBrightness(float brightness)
+{
+	BPrivate::AppServerLink link;
+	link.StartMessage(AS_SCREEN_SET_BRIGHTNESS);
+	link.Attach<int32>(ID());
+	link.Attach<float>(brightness);
+
+	status_t status = B_ERROR;
+	link.FlushWithReply(status);
+
+	return status;
+}
+
+
 void *
 BPrivateScreen::BaseAddress()
 {

src/kits/interface/Screen.cpp

@@ -333,6 +333,24 @@ BScreen::DPMSCapabilites()
 }
 
 
+status_t
+BScreen::GetBrightness(float* brightness)
+{
+	if (fScreen != NULL)
+		return fScreen->GetBrightness(brightness);
+	return B_ERROR;
+}
+
+
+status_t
+BScreen::SetBrightness(float brightness)
+{
+	if (fScreen != NULL)
+		return fScreen->SetBrightness(brightness);
+	return B_ERROR;
+}
+
+
 //	#pragma mark - Deprecated methods
 
 

src/preferences/screen/Constants.h

@@ -36,6 +36,7 @@ static const uint32 POP_TV_STANDARD_MSG = 'ptvs';
 static const uint32 UPDATE_DESKTOP_MSG = 'udsk';
 static const uint32 SLIDER_MODIFICATION_MSG = 'sldm';
 static const uint32 SLIDER_INVOKE_MSG = 'sldi';
+static const uint32 SLIDER_BRIGHTNESS_MSG = 'brig';
 static const uint32 SET_CUSTOM_REFRESH_MSG = 'scrf';
 static const uint32 DIM_COUNT_MSG = 'scrf';
 static const uint32 MAKE_INITIAL_MSG = 'mkin';

src/preferences/screen/ScreenWindow.cpp

@@ -506,6 +506,22 @@ ScreenWindow::ScreenWindow(ScreenSettings* settings)
 			.Add(fTVStandardField->CreateMenuBarLayoutItem(), 1, 6)
 		.End();
 
+	fBrightnessSlider = new BSlider("brightness", "Brightness",
+		NULL, 0, 255, B_HORIZONTAL);
+
+	status_t result = screen.GetBrightness(&fOriginalBrightness);
+	if (result == B_OK) {
+		fBrightnessSlider->SetModificationMessage(
+			new BMessage(SLIDER_BRIGHTNESS_MSG));
+		fBrightnessSlider->SetValue(fOriginalBrightness * 255);
+	} else {
+		// The driver does not support changing the brightness,
+		// so hide the slider
+		fBrightnessSlider->Hide();
+
+		fOriginalBrightness = -1;
+	}
+
 	// TODO: we don't support getting the screen's preferred settings
 	/* fDefaultsButton = new BButton(buttonRect, "DefaultsButton", "Defaults",
 		new BMessage(BUTTON_DEFAULTS_MSG));*/
@@ -529,7 +545,10 @@ ScreenWindow::ScreenWindow(ScreenSettings* settings)
 				.AddStrut(floorf(controlsBox->TopBorderOffset()) - 1)
 				.Add(screenBox)
 				.End()
-			.Add(controlsBox, 2)
+			.AddGroup(B_VERTICAL, 0, 1)
+				.Add(controlsBox, 2)
+				.Add(fBrightnessSlider)
+				.End()
 			.End()
 		.AddGroup(B_HORIZONTAL, B_USE_DEFAULT_SPACING)
 			.Add(fRevertButton)
@@ -1118,6 +1137,10 @@ ScreenWindow::MessageReceived(BMessage* message)
 
 			fScreenMode.Revert();
 			_UpdateActiveMode();
+
+			BScreen screen(this);
+			screen.SetBrightness(fOriginalBrightness);
+			fBrightnessSlider->SetValue(fOriginalBrightness * 255);
 			break;
 		}
 
@@ -1135,6 +1158,14 @@ ScreenWindow::MessageReceived(BMessage* message)
 			PostMessage(message, fMonitorView);
 			break;
 
+		case SLIDER_BRIGHTNESS_MSG:
+		{
+			BScreen screen(this);
+			screen.SetBrightness(message->FindInt32("be:value") / 255.f);
+			_CheckApplyEnabled();
+			break;
+		}
+
 		default:
 			BWindow::MessageReceived(message);
 	}
@@ -1214,8 +1245,13 @@ ScreenWindow::_CheckApplyEnabled()
 	uint32 rows;
 	BPrivate::get_workspaces_layout(&columns, &rows);
 
+	BScreen screen(this);
+	float brightness = -1;
+	screen.GetBrightness(&brightness);
+
 	fRevertButton->SetEnabled(columns != fOriginalWorkspacesColumns
 		|| rows != fOriginalWorkspacesRows
+		|| brightness != fOriginalBrightness
 		|| fSelected != fOriginal);
 }
 

src/preferences/screen/ScreenWindow.h

@@ -21,6 +21,7 @@
 class BBox;
 class BPopUpMenu;
 class BMenuField;
+class BSlider;
 class BSpinner;
 class BStringView;
 
@@ -95,6 +96,8 @@ private:
 			BPopUpMenu*		fTVStandardMenu;
 			BMenuField*		fTVStandardField;
 
+			BSlider*		fBrightnessSlider;
+
 			BButton*		fDefaultsButton;
 			BButton*		fApplyButton;
 			BButton*		fRevertButton;
@@ -110,6 +113,7 @@ private:
 
 			uint32			fOriginalWorkspacesColumns;
 			uint32			fOriginalWorkspacesRows;
+			float			fOriginalBrightness;
 			bool			fModified;
 };
 

src/servers/app/ProfileMessageSupport.cpp

@@ -155,6 +155,9 @@ string_for_message_code(uint32 code, BString& string)
 		CODE(AS_GET_DPMS_STATE);
 		CODE(AS_GET_DPMS_CAPABILITIES);
 
+		CODE(AS_SCREEN_SET_BRIGHTNESS);
+		CODE(AS_SCREEN_GET_BRIGHTNESS);
+
 		// Misc stuff
 		CODE(AS_GET_ACCELERANT_PATH);
 		CODE(AS_GET_DRIVER_PATH);

src/servers/app/ServerApp.cpp

@@ -3050,6 +3050,37 @@ ServerApp::_DispatchMessage(int32 code, BPrivate::LinkReceiver& link)
 			break;
 		}
 
+		case AS_SCREEN_SET_BRIGHTNESS:
+		{
+			STRACE(("ServerApp %s: AS_SCREEN_SET_BRIGHTNESS\n", Signature()));
+			int32 id;
+			link.Read<int32>(&id);
+
+			float brightness;
+			link.Read<float>(&brightness);
+
+			status_t status = fDesktop->HWInterface()->SetBrightness(brightness);
+			fLink.StartMessage(status);
+
+			fLink.Flush();
+			break;
+		}
+
+		case AS_SCREEN_GET_BRIGHTNESS:
+		{
+			STRACE(("ServerApp %s: AS_SCREEN_GET_BRIGHTNESS\n", Signature()));
+			int32 id;
+			link.Read<int32>(&id);
+
+			float brightness;
+			status_t result = fDesktop->HWInterface()->GetBrightness(&brightness);
+			fLink.StartMessage(result);
+			if (result == B_OK)
+				fLink.Attach<float>(brightness);
+			fLink.Flush();
+			break;
+		}
+
 		case AS_READ_BITMAP:
 		{
 			STRACE(("ServerApp %s: AS_READ_BITMAP\n", Signature()));

src/servers/app/drawing/BitmapHWInterface.cpp

@@ -176,6 +176,20 @@ BitmapHWInterface::DPMSCapabilities()
 }
 
 
+status_t
+BitmapHWInterface::SetBrightness(float)
+{
+	return B_UNSUPPORTED;
+}
+
+
+status_t
+BitmapHWInterface::GetBrightness(float*)
+{
+	return B_UNSUPPORTED;
+}
+
+
 RenderingBuffer*
 BitmapHWInterface::FrontBuffer() const
 {

src/servers/app/drawing/BitmapHWInterface.h

@@ -51,6 +51,9 @@ public:
 	virtual uint32				DPMSMode();
 	virtual uint32				DPMSCapabilities();
 
+	virtual status_t			SetBrightness(float);
+	virtual status_t			GetBrightness(float*);
+
 	// frame buffer access
 	virtual	RenderingBuffer*	FrontBuffer() const;
 	virtual	RenderingBuffer*	BackBuffer() const;

src/servers/app/drawing/DWindowHWInterface.cpp

@@ -912,6 +912,24 @@ DWindowHWInterface::DPMSCapabilities()
 }
 
 
+status_t
+DWindowHWInterface::SetBrightness(float brightness)
+{
+	AutoReadLocker _(this);
+
+	return BScreen().SetBrightness(brightness);
+}
+
+
+status_t
+DWindowHWInterface::GetBrightness(float* brightness)
+{
+	AutoReadLocker _(this);
+
+	return BScreen().GetBrightness(brightness);
+}
+
+
 uint32
 DWindowHWInterface::AvailableHWAcceleration() const
 {

src/servers/app/drawing/DWindowHWInterface.h

@@ -56,6 +56,9 @@ public:
 	virtual uint32				DPMSMode();
 	virtual uint32				DPMSCapabilities();
 
+	virtual status_t			SetBrightness(float);
+	virtual status_t			GetBrightness(float*);
+
 	// query for available hardware accleration and perform it
 	virtual	uint32				AvailableHWAcceleration() const;
 

src/servers/app/drawing/HWInterface.h

@@ -105,6 +105,9 @@ public:
 	virtual uint32				DPMSMode() = 0;
 	virtual uint32				DPMSCapabilities() = 0;
 
+	virtual status_t			SetBrightness(float) = 0;
+	virtual status_t			GetBrightness(float*) = 0;
+
 	virtual status_t			GetAccelerantPath(BString& path);
 	virtual status_t			GetDriverPath(BString& path);
 

src/servers/app/drawing/ViewHWInterface.cpp

@@ -734,6 +734,24 @@ ViewHWInterface::DPMSCapabilities()
 }
 
 
+status_t
+ViewHWInterface::SetBrightness(float)
+{
+	AutoReadLocker _(this);
+
+	return BScreen().SetBrightness(float);
+}
+
+
+status_t
+ViewHWInterface::GetBrightness(float*)
+{
+	AutoReadLocker _(this);
+
+	return BScreen().GetBrightness(float);
+}
+
+
 sem_id
 ViewHWInterface::RetraceSemaphore()
 {

src/servers/app/drawing/ViewHWInterface.h

@@ -51,6 +51,9 @@ public:
 	virtual uint32				DPMSMode();
 	virtual uint32				DPMSCapabilities();
 
+	virtual status_t			SetBrightness(float);
+	virtual status_t			GetBrightness(float*);
+
 	// frame buffer access
 	virtual	RenderingBuffer*	FrontBuffer() const;
 	virtual	RenderingBuffer*	BackBuffer() const;

src/servers/app/drawing/interface/html5/HTML5HWInterface.cpp

@@ -516,6 +516,20 @@ HTML5HWInterface::RetraceSemaphore()
 }
 
 
+status_t
+HTML5HWInterface::SetBrightness(float)
+{
+	return B_UNSUPPORTED;
+}
+
+
+status_t
+HTML5HWInterface::GetBrightness(float*)
+{
+	return B_UNSUPPORTED;
+}
+
+
 status_t
 HTML5HWInterface::WaitForRetrace(bigtime_t timeout)
 {

src/servers/app/drawing/interface/html5/HTML5HWInterface.h

@@ -62,6 +62,9 @@ virtual status_t					SetDPMSMode(uint32 state);
 virtual uint32						DPMSMode();
 virtual uint32						DPMSCapabilities();
 
+virtual status_t			SetBrightness(float);
+virtual status_t			GetBrightness(float*);
+
 		// cursor handling
 virtual	void						SetCursor(ServerCursor* cursor);
 virtual	void						SetCursorVisible(bool visible);

src/servers/app/drawing/interface/local/AccelerantHWInterface.cpp

@@ -133,6 +133,10 @@ AccelerantHWInterface::AccelerantHWInterface()
 	fAccDPMSMode(NULL),
 	fAccSetDPMSMode(NULL),
 
+	// brightness hooks
+	fAccSetBrightness(NULL),
+	fAccGetBrightness(NULL),
+
 	// overlay hooks
 	fAccOverlayCount(NULL),
 	fAccOverlaySupportedSpaces(NULL),
@@ -401,6 +405,10 @@ AccelerantHWInterface::_SetupDefaultHooks()
 	fAccDPMSMode = (dpms_mode)fAccelerantHook(B_DPMS_MODE, NULL);
 	fAccSetDPMSMode = (set_dpms_mode)fAccelerantHook(B_SET_DPMS_MODE, NULL);
 
+	// brightness
+	fAccGetBrightness = (get_brightness)fAccelerantHook(B_GET_BRIGHTNESS, NULL);
+	fAccSetBrightness = (set_brightness)fAccelerantHook(B_SET_BRIGHTNESS, NULL);
+
 	return B_OK;
 }
 
@@ -1113,6 +1121,30 @@ AccelerantHWInterface::DPMSCapabilities()
 }
 
 
+status_t
+AccelerantHWInterface::SetBrightness(float brightness)
+{
+	AutoReadLocker _(this);
+
+	if (!fAccSetBrightness)
+		return B_UNSUPPORTED;
+
+	return fAccSetBrightness(brightness);
+}
+
+
+status_t
+AccelerantHWInterface::GetBrightness(float* brightness)
+{
+	AutoReadLocker _(this);
+
+	if (!fAccGetBrightness)
+		return B_UNSUPPORTED;
+
+	return fAccGetBrightness(brightness);
+}
+
+
 status_t
 AccelerantHWInterface::GetAccelerantPath(BString& string)
 {

src/servers/app/drawing/interface/local/AccelerantHWInterface.h

@@ -56,6 +56,9 @@ public:
 	virtual uint32				DPMSMode();
 	virtual uint32				DPMSCapabilities();
 
+	virtual status_t			SetBrightness(float);
+	virtual status_t			GetBrightness(float*);
+
 	virtual status_t			GetAccelerantPath(BString& path);
 	virtual status_t			GetDriverPath(BString& path);
 
@@ -159,6 +162,10 @@ private:
 			dpms_mode			fAccDPMSMode;
 			set_dpms_mode		fAccSetDPMSMode;
 
+			// brightness hooks
+			set_brightness		fAccSetBrightness;
+			get_brightness		fAccGetBrightness;
+
 			// overlay hooks
 			overlay_count				fAccOverlayCount;
 			overlay_supported_spaces	fAccOverlaySupportedSpaces;

src/servers/app/drawing/interface/remote/RemoteHWInterface.cpp

@@ -468,6 +468,20 @@ RemoteHWInterface::DPMSCapabilities()
 }
 
 
+status_t
+RemoteHWInterface::SetBrightness(float)
+{
+	return B_UNSUPPORTED;
+}
+
+
+status_t
+RemoteHWInterface::GetBrightness(float*)
+{
+	return B_UNSUPPORTED;
+}
+
+
 sem_id
 RemoteHWInterface::RetraceSemaphore()
 {

src/servers/app/drawing/interface/remote/RemoteHWInterface.h

@@ -59,6 +59,9 @@ virtual status_t					SetDPMSMode(uint32 state);
 virtual uint32						DPMSMode();
 virtual uint32						DPMSCapabilities();
 
+virtual status_t			SetBrightness(float);
+virtual status_t			GetBrightness(float*);
+
 		// cursor handling
 virtual	void						SetCursor(ServerCursor* cursor);
 virtual	void						SetCursorVisible(bool visible);