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, 4 insertions, 4 deletions

diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index 8eda7b60df8f..ad31983b43eb 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -1881,7 +1881,7 @@ static int fbcon_scroll(struct vc_data *vc, int t, int b, int dir,
                         scr_memsetw((unsigned short *) (vc->vc_origin +
                                                         vc->vc_size_row *
                                                         (b - count)),
-                                    vc->vc_video_erase_char,
+                                    vc->vc_scrl_erase_char,
                                     vc->vc_size_row * count);
                         return 1;
                         break;
@@ -1953,7 +1953,7 @@ static int fbcon_scroll(struct vc_data *vc, int t, int b, int dir,
                         scr_memsetw((unsigned short *) (vc->vc_origin +
                                                         vc->vc_size_row *
                                                         (b - count)),
-                                    vc->vc_video_erase_char,
+                                    vc->vc_scrl_erase_char,
                                     vc->vc_size_row * count);
                         return 1;
                 }
@@ -1972,7 +1972,7 @@ static int fbcon_scroll(struct vc_data *vc, int t, int b, int dir,
                         scr_memsetw((unsigned short *) (vc->vc_origin +
                                                         vc->vc_size_row *
                                                         t),
-                                    vc->vc_video_erase_char,
+                                    vc->vc_scrl_erase_char,
                                     vc->vc_size_row * count);
                         return 1;
                         break;
@@ -2042,7 +2042,7 @@ static int fbcon_scroll(struct vc_data *vc, int t, int b, int dir,
                         scr_memsetw((unsigned short *) (vc->vc_origin +
                                                         vc->vc_size_row *
                                                         t),
-                                    vc->vc_video_erase_char,
+                                    vc->vc_scrl_erase_char,
                                     vc->vc_size_row * count);
                         return 1;
                 }