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vt: fix background color on line feed
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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>
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Jan Engelhardt authored and Linus Torvalds committed Apr 29, 2008
1 parent 3265e66 commit c9e587a
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Showing 6 changed files with 14 additions and 12 deletions.
7 changes: 4 additions & 3 deletions drivers/char/vt.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -301,7 +301,7 @@ static void scrup(struct vc_data *vc, unsigned int t, unsigned int b, int nr)
d = (unsigned short *)(vc->vc_origin + vc->vc_size_row * t);
s = (unsigned short *)(vc->vc_origin + vc->vc_size_row * (t + nr));
scr_memmovew(d, s, (b - t - nr) * vc->vc_size_row);
scr_memsetw(d + (b - t - nr) * vc->vc_cols, vc->vc_video_erase_char,
scr_memsetw(d + (b - t - nr) * vc->vc_cols, vc->vc_scrl_erase_char,
vc->vc_size_row * nr);
}

Expand All @@ -319,7 +319,7 @@ static void scrdown(struct vc_data *vc, unsigned int t, unsigned int b, int nr)
s = (unsigned short *)(vc->vc_origin + vc->vc_size_row * t);
step = vc->vc_cols * nr;
scr_memmovew(s + step, s, (b - t - nr) * vc->vc_size_row);
scr_memsetw(s, vc->vc_video_erase_char, 2 * step);
scr_memsetw(s, vc->vc_scrl_erase_char, 2 * step);
}

static void do_update_region(struct vc_data *vc, unsigned long start, int count)
Expand Down Expand Up @@ -400,7 +400,7 @@ static u8 build_attr(struct vc_data *vc, u8 _color, u8 _intensity, u8 _blink,
* Bit 7 : blink
*/
{
u8 a = vc->vc_color;
u8 a = _color;
if (!vc->vc_can_do_color)
return _intensity |
(_italic ? 2 : 0) |
Expand Down Expand Up @@ -434,6 +434,7 @@ static void update_attr(struct vc_data *vc)
vc->vc_blink, vc->vc_underline,
vc->vc_reverse ^ vc->vc_decscnm, vc->vc_italic);
vc->vc_video_erase_char = (build_attr(vc, vc->vc_color, 1, vc->vc_blink, 0, vc->vc_decscnm, 0) << 8) | ' ';
vc->vc_scrl_erase_char = (build_attr(vc, vc->vc_def_color, 1, false, false, false, false) << 8) | ' ';
}

/* Note: inverting the screen twice should revert to the original state */
Expand Down
8 changes: 4 additions & 4 deletions drivers/video/console/fbcon.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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;
}
Expand All @@ -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;
Expand Down Expand Up @@ -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;
}
Expand Down
2 changes: 1 addition & 1 deletion drivers/video/console/mdacon.c
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Original file line number Diff line number Diff line change
Expand Up @@ -531,7 +531,7 @@ static void mdacon_cursor(struct vc_data *c, int mode)

static int mdacon_scroll(struct vc_data *c, int t, int b, int dir, int lines)
{
u16 eattr = mda_convert_attr(c->vc_video_erase_char);
u16 eattr = mda_convert_attr(c->vc_scrl_erase_char);

if (!lines)
return 0;
Expand Down
4 changes: 2 additions & 2 deletions drivers/video/console/sticon.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
}

Expand Down
4 changes: 2 additions & 2 deletions drivers/video/console/vgacon.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1350,7 +1350,7 @@ static int vgacon_scroll(struct vc_data *c, int t, int b, int dir,
} else
c->vc_origin += delta;
scr_memsetw((u16 *) (c->vc_origin + c->vc_screenbuf_size -
delta), c->vc_video_erase_char,
delta), c->vc_scrl_erase_char,
delta);
} else {
if (oldo - delta < vga_vram_base) {
Expand All @@ -1363,7 +1363,7 @@ static int vgacon_scroll(struct vc_data *c, int t, int b, int dir,
} else
c->vc_origin -= delta;
c->vc_scr_end = c->vc_origin + c->vc_screenbuf_size;
scr_memsetw((u16 *) (c->vc_origin), c->vc_video_erase_char,
scr_memsetw((u16 *) (c->vc_origin), c->vc_scrl_erase_char,
delta);
}
c->vc_scr_end = c->vc_origin + c->vc_screenbuf_size;
Expand Down
1 change: 1 addition & 0 deletions include/linux/console_struct.h
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Original file line number Diff line number Diff line change
Expand Up @@ -53,6 +53,7 @@ struct vc_data {
unsigned short vc_hi_font_mask; /* [#] Attribute set for upper 256 chars of font or 0 if not supported */
struct console_font vc_font; /* Current VC font set */
unsigned short vc_video_erase_char; /* Background erase character */
unsigned short vc_scrl_erase_char; /* Erase character for scroll */
/* VT terminal data */
unsigned int vc_state; /* Escape sequence parser state */
unsigned int vc_npar,vc_par[NPAR]; /* Parameters of current escape sequence */
Expand Down

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