vt: fix background color on line feed

A command that causes a line feed while a background color is active,
such as

	perl -e 'print "x" x 60, "\e[44m", "x" x 40, "\e[0m\n"'
and
	perl -e 'print "x" x 40, "\e[44m\n", "x" x 40, "\e[0m\n"'

causes the line that was started as a result of the line feed to be completely
filled with the currently active background color instead of the default
color.

When scrolling, part of the current screen is memcpy'd/memmove'd to the new
region, and the new line(s) that will appear as a result are cleared using
memset.  However, the lines are cleared with vc->vc_video_erase_char, causing
them to be colored with the currently active background color.  This is
different from X11 terminal emulators which always paint the new lines with
the default background color (e.g.  `xterm -bg black`).

The clear operation (\e[1J and \e[2J) also use vc_video_erase_char, so a new
vc->vc_scrl_erase_char is introduced with contains the erase character used
for scrolling, which is built from vc->vc_def_color instead of vc->vc_color.

Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/video/console/sticon.c b/drivers/video/console/sticon.c
index 67a682d6cc7b..a11cc2fdd4cd 100644
--- a/drivers/video/console/sticon.c
+++ b/drivers/video/console/sticon.c
@@ -170,12 +170,12 @@ static int sticon_scroll(struct vc_data *conp, int t, int b, int dir, int count)
     switch (dir) {
     case SM_UP:
         sti_bmove(sti, t + count, 0, t, 0, b - t - count, conp->vc_cols);
-        sti_clear(sti, b - count, 0, count, conp->vc_cols, conp->vc_video_erase_char);
+        sti_clear(sti, b - count, 0, count, conp->vc_cols, conp->vc_scrl_erase_char);
         break;
 
     case SM_DOWN:
         sti_bmove(sti, t, 0, t + count, 0, b - t - count, conp->vc_cols);
-        sti_clear(sti, t, 0, count, conp->vc_cols, conp->vc_video_erase_char);
+        sti_clear(sti, t, 0, count, conp->vc_cols, conp->vc_scrl_erase_char);
         break;
     }