Revert "vt: fix background color on line feed"

This reverts commit c9e587abfdec2c2aaa55fab83bcb4972e2f84f9b, and the
subsequent commits that fixed it up:

- afa9b649 "fbcon: prevent cursor disappearance after switching to 512
character font"

- d850a2fa "vt/fbcon: fix background color on line feed"

- 7fe3915a "vt/fbcon: update scrl_erase_char after 256/512-glyph font
switch"

by request of Alan Cox. Quoth Alan:
"Unfortunately it's wrong and its been causing breakages because
various apps like ncurses expect our previous (and correct)
behaviour."

Alexander sent out a similar patch.

Requested-by: Alan Cox <[e-mail]>
Tested-by: Jan Engelhardt <[e-mail]>
Cc: Alexander V. Lukyanov <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/char/vt.c

···
 	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_scrl_erase_char,
+	scr_memsetw(d + (b - t - nr) * vc->vc_cols, vc->vc_video_erase_char,
 		    vc->vc_size_row * 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_scrl_erase_char, 2 * step);
+	scr_memsetw(s, vc->vc_video_erase_char, 2 * step);
 }
 
 static void do_update_region(struct vc_data *vc, unsigned long start, int count)
···
 	              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, vc->vc_decscnm, false) << 8) | ' ';
 }
 
 /* Note: inverting the screen twice should revert to the original state */

drivers/video/console/fbcon.c

···
 	struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
 	struct display *p = &fb_display[vc->vc_num];
 	int scroll_partial = info->flags & FBINFO_PARTIAL_PAN_OK;
-	unsigned short saved_ec;
-	int ret;
 
 	if (fbcon_is_inactive(vc, info))
 		return -EINVAL;
···
 	 * ++Andrew: Only use ypan on hardware text mode when scrolling the
 	 *           whole screen (prevents flicker).
 	 */
-
-	saved_ec = vc->vc_video_erase_char;
-	vc->vc_video_erase_char = vc->vc_scrl_erase_char;
-
-	ret = 0;
 
 	switch (dir) {
 	case SM_UP:
···
 			scr_memsetw((unsigned short *) (vc->vc_origin +
 							vc->vc_size_row *
 							(b - count)),
-				    vc->vc_scrl_erase_char,
+				    vc->vc_video_erase_char,
 				    vc->vc_size_row * count);
-			ret = 1;
+			return 1;
 			break;
 
 		case SCROLL_WRAP_MOVE:
···
 			scr_memsetw((unsigned short *) (vc->vc_origin +
 							vc->vc_size_row *
 							(b - count)),
-				    vc->vc_scrl_erase_char,
+				    vc->vc_video_erase_char,
 				    vc->vc_size_row * count);
-			ret = 1;
-			break;
+			return 1;
 		}
 		break;
 
···
 			scr_memsetw((unsigned short *) (vc->vc_origin +
 							vc->vc_size_row *
 							t),
-				    vc->vc_scrl_erase_char,
+				    vc->vc_video_erase_char,
 				    vc->vc_size_row * count);
-			ret = 1;
+			return 1;
 			break;
 
 		case SCROLL_WRAP_MOVE:
···
 			scr_memsetw((unsigned short *) (vc->vc_origin +
 							vc->vc_size_row *
 							t),
-				    vc->vc_scrl_erase_char,
+				    vc->vc_video_erase_char,
 				    vc->vc_size_row * count);
-			ret = 1;
-			break;
+			return 1;
 		}
-		break;
 	}
-	vc->vc_video_erase_char = saved_ec;
-	return ret;
+	return 0;
 }
 
 
···
 			c = vc->vc_video_erase_char;
 			vc->vc_video_erase_char =
 			    ((c & 0xfe00) >> 1) | (c & 0xff);
-			c = vc->vc_scrl_erase_char;
-			vc->vc_scrl_erase_char =
-			    ((c & 0xFE00) >> 1) | (c & 0xFF);
 			vc->vc_attr >>= 1;
 		}
 	} else if (!vc->vc_hi_font_mask && cnt == 512) {
···
 			if (vc->vc_can_do_color) {
 				vc->vc_video_erase_char =
 				    ((c & 0xff00) << 1) | (c & 0xff);
-				c = vc->vc_scrl_erase_char;
-				vc->vc_scrl_erase_char =
-				    ((c & 0xFF00) << 1) | (c & 0xFF);
 				vc->vc_attr <<= 1;
-			} else {
+			} else
 				vc->vc_video_erase_char = c & ~0x100;
-				vc->vc_scrl_erase_char = c & ~0x100;
-			}
 		}
 
 	}

drivers/video/console/mdacon.c

···
 
 static int mdacon_scroll(struct vc_data *c, int t, int b, int dir, int lines)
 {
-	u16 eattr = mda_convert_attr(c->vc_scrl_erase_char);
+	u16 eattr = mda_convert_attr(c->vc_video_erase_char);
 
 	if (!lines)
 		return 0;

drivers/video/console/sticon.c

···
     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_scrl_erase_char);
+	sti_clear(sti, b - count, 0, count, conp->vc_cols, conp->vc_video_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_scrl_erase_char);
+	sti_clear(sti, t, 0, count, conp->vc_cols, conp->vc_video_erase_char);
 	break;
     }
 

drivers/video/console/vgacon.c

···
 		} else
 			c->vc_origin += delta;
 		scr_memsetw((u16 *) (c->vc_origin + c->vc_screenbuf_size -
-				     delta), c->vc_scrl_erase_char,
+				     delta), c->vc_video_erase_char,
 			    delta);
 	} else {
 		if (oldo - delta < vga_vram_base) {
···
 		} else
 			c->vc_origin -= delta;
 		c->vc_scr_end = c->vc_origin + c->vc_screenbuf_size;
-		scr_memsetw((u16 *) (c->vc_origin), c->vc_scrl_erase_char,
+		scr_memsetw((u16 *) (c->vc_origin), c->vc_video_erase_char,
 			    delta);
 	}
 	c->vc_scr_end = c->vc_origin + c->vc_screenbuf_size;

include/linux/console_struct.h

···
 	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 */