[PATCH] vt: fix background color on line feed

[PATCH] vt: fix background color on line feed

[Jan Engelhardt]

commit c5180a555ced08a7e3011c16ef796e47569ae907
Author: Jan Engelhardt <jengelh@computergmbh.de>
Date:   Thu Apr 24 22:40:24 2008 +0200

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.
    
Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
---
 drivers/char/vt.c              |    7 ++++---
 drivers/video/console/fbcon.c  |    8 ++++----
 drivers/video/console/mdacon.c |    2 +-
 drivers/video/console/sticon.c |    4 ++--
 drivers/video/console/vgacon.c |    4 ++--
 include/linux/console_struct.h |    1 +
 6 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/drivers/char/vt.c b/drivers/char/vt.c
index 9b58b89..159c9e2 100644
--- a/drivers/char/vt.c
+++ b/drivers/char/vt.c
@@ -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);
 }
 
@@ -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)
@@ -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) |
@@ -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 */
diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index 0222824..ca2a543 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -1882,7 +1882,7 @@ 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;
@@ -1954,7 +1954,7 @@ 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;
 		}
@@ -1973,7 +1973,7 @@ 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;
@@ -2043,7 +2043,7 @@ 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;
 		}
diff --git a/drivers/video/console/mdacon.c b/drivers/video/console/mdacon.c
index bd8d995..38a296b 100644
--- a/drivers/video/console/mdacon.c
+++ b/drivers/video/console/mdacon.c
@@ -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;
diff --git a/drivers/video/console/sticon.c b/drivers/video/console/sticon.c
index 67a682d..a11cc2f 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;
     }
 
diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index 6df29a6..bd1f57b 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -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) {
@@ -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;
diff --git a/include/linux/console_struct.h b/include/linux/console_struct.h
index d71f7c0..b03f80a 100644
--- a/include/linux/console_struct.h
+++ b/include/linux/console_struct.h
@@ -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 */

Re: [PATCH] vt: fix background color on line feed

[Andrew Morton]

On Sun, 27 Apr 2008 03:12:44 +0200 (CEST) Jan Engelhardt <jengelh@computergmbh.de> wrote:

> commit c5180a555ced08a7e3011c16ef796e47569ae907
> Author: Jan Engelhardt <jengelh@computergmbh.de>
> Date:   Thu Apr 24 22:40:24 2008 +0200
> 
> 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.

Thanks.

It would be better if the the changelog were to also describe the cause of
the bug, and how the patch fixes it.

Re: [PATCH] vt: fix background color on line feed

[Jan Engelhardt]

On Monday 2008-04-28 04:36, Andrew Morton wrote:
>> commit c5180a555ced08a7e3011c16ef796e47569ae907
>> Author: Jan Engelhardt <jengelh@computergmbh.de>
>> Date:   Thu Apr 24 22:40:24 2008 +0200
>> 
>> 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.
>
>Thanks.
>
>It would be better if the the changelog were to also describe the cause of
>the bug, and how the patch fixes it.
>
Please append:

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.

Re: [PATCH] vt: fix background color on line feed

[Jan Engelhardt]

On Monday 2008-04-28 08:46, Jan Engelhardt wrote:
>On Monday 2008-04-28 04:36, Andrew Morton wrote:
>>> commit c5180a555ced08a7e3011c16ef796e47569ae907
>>> Author: Jan Engelhardt <jengelh@computergmbh.de>
>>> Date:   Thu Apr 24 22:40:24 2008 +0200
>>> 
>>> 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.
>>
>>Thanks.
>>
>>It would be better if the the changelog were to also describe the cause of
>>the bug, and how the patch fixes it.
>>
>Please append:
>[...]

I think your mailer has whitespace problems -- all whitespaces
got replaced by two, even intrasentence after an "e.g."  :-P

Re: [PATCH] vt: fix background color on line feed

[Andrew Morton]

On Tue, 29 Apr 2008 20:17:26 +0200 (CEST)
Jan Engelhardt <jengelh@medozas.de> wrote:

> 
> On Monday 2008-04-28 08:46, Jan Engelhardt wrote:
> >On Monday 2008-04-28 04:36, Andrew Morton wrote:
> >>> commit c5180a555ced08a7e3011c16ef796e47569ae907
> >>> Author: Jan Engelhardt <jengelh@computergmbh.de>
> >>> Date:   Thu Apr 24 22:40:24 2008 +0200
> >>> 
> >>> 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.
> >>
> >>Thanks.
> >>
> >>It would be better if the the changelog were to also describe the cause of
> >>the bug, and how the patch fixes it.
> >>
> >Please append:
> >[...]
> 
> I think your mailer has whitespace problems -- all whitespaces
> got replaced by two,

That's the default (ie: only ;)) behaviour of my editor's
reformat-paragraph command.

> even intrasentence after an "e.g."  :-P

Perhaps I should fix that.  Only I wrote it, umm, 22 years ago and forget
how it works.