Add debug option to disable the on-screen debug output's paging by default, for

cases such as USB keyboards where the keyboard no longer functions once the 
kernel is entered and the USB stack initializes.

Implements #7561.



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@41736 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/boot/loader/menu.cpp

@@ -829,6 +829,13 @@ add_debug_menu()
 	item->SetHelpText("Displays debug output on screen while the system "
 		"is booting, instead of the normal boot logo.");
 
+	menu->AddItem(item
+		= new(nothrow) MenuItem("Disable on screen paging"));
+	item->SetData("disable_onscreen_paging");
+	item->SetType(MENU_ITEM_MARKABLE);
+	item->SetHelpText("Disables paging when on screen debug output is "
+		"enabled.");
+
 	menu->AddItem(item = new(nothrow) MenuItem("Enable debug syslog"));
 	item->SetType(MENU_ITEM_MARKABLE);
 	item->SetMarked(gKernelArgs.keep_debug_output_buffer);

src/system/kernel/debug/blue_screen.cpp

@@ -14,6 +14,7 @@
 #include <console.h>
 #include <debug.h>
 #include <arch/debug_console.h>
+#include <safemode.h>
 
 #include <string.h>
 #include <stdio.h>
@@ -603,7 +604,8 @@ blue_screen_init(void)
 		return B_ERROR;
 
 	sModule = &gFrameBufferConsoleModule;
-	sScreen.paging = true;
+	sScreen.paging = !get_safemode_boolean(
+		"disable_onscreen_paging", false);
 	sScreen.paging_timeout = false;
 
 	add_debugger_command("paging", set_paging, "Enable or disable paging");