On 08/18/2017 01:21 PM, Geert Uytterhoeven wrote:

Hi David,

On Tue, Aug 1, 2017 at 6:35 PM, David Lechner [off-list ref] wrote:

quoted

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>

quoted

--- 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.
+

Given the standard console palette contains 16 colors, why limit this to
the first 8 colors, and not 0 to 15?

Good question. I think in some of my previous attempts there was a 0x7 
mask involved somewhere and this is a carryover from that. But, after 
having looked at this again, I don't see a reason for limiting to 7.