[3DS] Disable bottom screen backlight

SourceX/platform/ctr/system.cpp

@@ -5,6 +5,44 @@
 
 bool isN3DS;
 
+aptHookCookie cookie;
+
+void aptHookFunc(APT_HookType hookType, void *param)
+{
+	switch (hookType) {
+		case APTHOOK_ONSUSPEND:
+			ctr_lcd_backlight_on();
+			break;
+		case APTHOOK_ONSLEEP:
+			break;
+		case APTHOOK_ONRESTORE:
+			ctr_lcd_backlight_off();
+			break;
+		case APTHOOK_ONWAKEUP:
+			ctr_lcd_backlight_off();
+			break;
+		case APTHOOK_ONEXIT:
+			ctr_lcd_backlight_on();
+			break;
+		default:
+			break;
+	}
+}
+
+void ctr_lcd_backlight_on()
+{
+	gspLcdInit();
+	GSPLCD_PowerOnBacklight(GSPLCD_SCREEN_BOTTOM);
+	gspLcdExit();
+}
+
+void ctr_lcd_backlight_off()
+{
+	gspLcdInit();
+	GSPLCD_PowerOffBacklight(GSPLCD_SCREEN_BOTTOM);
+	gspLcdExit();
+}
+
 bool ctr_check_dsp()
 {
 	FILE *dsp = fopen("sdmc:/3ds/dspfirm.cdc", "r");
@@ -27,10 +65,15 @@ void ctr_sys_init()
 	if( ctr_check_dsp() == false )
 		exit(0);
 
+	aptHook(&cookie, aptHookFunc, NULL);
+
 	APT_CheckNew3DS(&isN3DS);
 	if(isN3DS)
 		osSetSpeedupEnable(true);
 
+	ctr_lcd_backlight_off();
+	atexit([]() { ctr_lcd_backlight_on(); });
+
 	romfsInit();
 	atexit([]() { romfsExit(); });
 }

SourceX/platform/ctr/system.h

@@ -1,5 +1,8 @@
 #pragma once
 
+void ctr_lcd_backlight_on();
+void ctr_lcd_backlight_off();
+
 bool ctr_check_dsp();
 
 void ctr_sys_init();