boot_loader_openfirmware: Preparations for frame buffer

Initialize the frame buffer as not enabled. Add checks for this condition
and for the debug boot option to the video functions.

Code is adapted from bios_ia32 platform. Part of ticket #6105.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@38299 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/boot/platform/openfirmware/video.cpp

@@ -1,15 +1,21 @@
 /*
  * Copyright 2004, Axel Dörfler, [email protected].
+ * Copyright 2010 Andreas Färber <[email protected]>
  * All rights reserved. Distributed under the terms of the MIT License.
  */
 
 
 #include <boot/platform.h>
+#include <boot/stage2.h>
 
 
 extern "C" void
 platform_switch_to_logo(void)
 {
+	// in debug mode, we'll never show the logo
+	if ((platform_boot_options() & BOOT_OPTION_DEBUG_OUTPUT) != 0)
+		return;
+
 	// ToDo: implement me
 }
 
@@ -17,13 +23,21 @@ platform_switch_to_logo(void)
 extern "C" void
 platform_switch_to_text_mode(void)
 {
+	// nothing to do if we're in text mode
+	if (!gKernelArgs.frame_buffer.enabled)
+		return;
+
 	// ToDo: implement me
+
+	gKernelArgs.frame_buffer.enabled = false;
 }
 
 
 extern "C" status_t
 platform_init_video(void)
 {
+	gKernelArgs.frame_buffer.enabled = false;
+
 	// ToDo: implement me
 	return B_OK;
 }