panic() could hang in the early boot process in case it was called before

the blue screen was initialized - blue_screen_enter() now returns wether
or not it has been initialized already (there will only be serial output
in that case).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22491 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/kernel/debug/blue_screen.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright 2005-2006, Axel Dörfler, [email protected]. All rights reserved.
+ * Copyright 2005-2007, Axel Dörfler, [email protected]. All rights reserved.
  * Distributed under the terms of the MIT License.
  */
 
@@ -486,7 +486,7 @@ blue_screen_init(void)
 }
 
 
-void
+status_t
 blue_screen_enter(bool debugOutput)
 {
 	sScreen.attr = debugOutput ? 0xf0 : 0x0f;
@@ -494,12 +494,16 @@ blue_screen_enter(bool debugOutput)
 	sScreen.x = sScreen.y = 0;
 	sScreen.state = CONSOLE_STATE_NORMAL;
 
+	if (sModule == NULL)
+		return B_NO_INIT;
+
 	sModule->get_size(&sScreen.columns, &sScreen.rows);
 #if !NO_CLEAR
 	sModule->clear(sScreen.attr);
 #else
 	sModule->fill_glyph(0, sScreen.y, sScreen.columns, 3, ' ', sScreen.attr);
 #endif
+	return B_OK;
 }
 
 

src/system/kernel/debug/blue_screen.h

@@ -1,5 +1,5 @@
 /*
- * Copyright 2005-2006, Axel Dörfler, [email protected]. All rights reserved.
+ * Copyright 2005-2007, Axel Dörfler, [email protected]. All rights reserved.
  * Distributed under the terms of the MIT License.
  */
 #ifndef BLUE_SCREEN_H
@@ -14,7 +14,7 @@ extern "C" {
 #endif
 
 status_t blue_screen_init(void);
-void blue_screen_enter(bool debugOutput);
+status_t blue_screen_enter(bool debugOutput);
 
 char blue_screen_getchar(void);
 void blue_screen_putchar(char c);

src/system/kernel/debug/debug.c

@@ -893,8 +893,8 @@ kernel_debugger(const char *message)
 	}
 
 	if (sBlueScreenOutput) {
-		sBlueScreenEnabled = true;
+		if (blue_screen_enter(false) == B_OK)
-		blue_screen_enter(false);
+			sBlueScreenEnabled = true;
 	}
 
 	if (message)