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Commit c9e587ab authored by Jan Engelhardt's avatar Jan Engelhardt Committed by Linus Torvalds
Browse files

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: default avatarJan 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3265e66b

drivers/char/vt.c

+4 −3
Original line number Diff line number Diff line
@@ -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 */

drivers/video/console/fbcon.c

+4 −4
Original line number Diff line number Diff line
@@ -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;

		}

drivers/video/console/mdacon.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

drivers/video/console/sticon.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

    }

drivers/video/console/vgacon.c

+2 −2
Original line number Diff line number Diff line
@@ -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;