fbcon: add fbcon=margin:<color> command line option

This adds a new command line option to select the fbcon margin color.

The motivation for this is screens where black does not blend into the
physical surroundings of the screen. For example, using an LCD (not the
backlit kind), white text on a black background is hard to read, so
inverting the colors is preferred. However, when you do this, most of the
screen is filled with white but the margins are still filled with black.
This makes a big, black, backwards 'L' on the screen. By setting
fbcon=margin:7, the margins will be filled with white and the LCD looks as
expected.

Signed-off-by: David Lechner <david@lechnology.com>
[b.zolnierkie: ported over fbcon changes]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/Documentation/fb/fbcon.txt b/Documentation/fb/fbcon.txt
index 4a9739abc860..1822b190ccd6 100644
--- a/Documentation/fb/fbcon.txt
+++ b/Documentation/fb/fbcon.txt
@@ -148,6 +148,13 @@ C. Boot options
 	Actually, the underlying fb driver is totally ignorant of console
 	rotation.
 
+5. fbcon=margin:<color>
+
+	This option specifies the color of the margins. The margins are the
+	leftover area at the right and the bottom of the screen that are not
+	used by text. By default, this area will be black. The 'color' value
+	is 0 to 7 where 0 is black and 7 is white.
+
 C. Attaching, Detaching and Unloading
 
 Before going on how to attach, detach and unload the framebuffer console, an