fbdev: Garbage collect fbdev scrolling acceleration, part 1 (from TODO list)drm-misc-next-2021-10-14

Scroll acceleration is disabled in fbcon by hard-wiring
p->scrollmode = SCROLL_REDRAW. Remove the obsolete code in fbcon.c
and fbdev/core/

Signed-off-by: Claudio Suarez <cssk@net-c.es>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/YVXTYqszZix9TxjJ@gineta.localdomain

1 files changed, 20 insertions, 489 deletions

diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 22bb3892f6bd..99ecd9a6d844 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -173,8 +173,6 @@ static void fbcon_putcs(struct vc_data *vc, const unsigned short *s,
 			int count, int ypos, int xpos);
 static void fbcon_clear_margins(struct vc_data *vc, int bottom_only);
 static void fbcon_cursor(struct vc_data *vc, int mode);
-static void fbcon_bmove(struct vc_data *vc, int sy, int sx, int dy, int dx,
-			int height, int width);
 static int fbcon_switch(struct vc_data *vc);
 static int fbcon_blank(struct vc_data *vc, int blank, int mode_switch);
 static void fbcon_set_palette(struct vc_data *vc, const unsigned char *table);
@@ -182,16 +180,8 @@ static void fbcon_set_palette(struct vc_data *vc, const unsigned char *table);
 /*
  *  Internal routines
  */
-static __inline__ void ywrap_up(struct vc_data *vc, int count);
-static __inline__ void ywrap_down(struct vc_data *vc, int count);
-static __inline__ void ypan_up(struct vc_data *vc, int count);
-static __inline__ void ypan_down(struct vc_data *vc, int count);
-static void fbcon_bmove_rec(struct vc_data *vc, struct fbcon_display *p, int sy, int sx,
-			    int dy, int dx, int height, int width, u_int y_break);
 static void fbcon_set_disp(struct fb_info *info, struct fb_var_screeninfo *var,
 			   int unit);
-static void fbcon_redraw_move(struct vc_data *vc, struct fbcon_display *p,
-			      int line, int count, int dy);
 static void fbcon_modechanged(struct fb_info *info);
 static void fbcon_set_all_vcs(struct fb_info *info);
 static void fbcon_start(void);
@@ -1136,14 +1126,6 @@ static void fbcon_init(struct vc_data *vc, int init)
 	ops->graphics = 0;
 
 	/*
-	 * No more hw acceleration for fbcon.
-	 *
-	 * FIXME: Garbage collect all the now dead code after sufficient time
-	 * has passed.
-	 */
-	p->scrollmode = SCROLL_REDRAW;
-
-	/*
 	 *  ++guenther: console.c:vc_allocate() relies on initializing
 	 *  vc_{cols,rows}, but we must not set those if we are only
 	 *  resizing the console.
@@ -1229,14 +1211,13 @@ finished:
  *  This system is now divided into two levels because of complications
  *  caused by hardware scrolling. Top level functions:
  *
- *	fbcon_bmove(), fbcon_clear(), fbcon_putc(), fbcon_clear_margins()
+ *	fbcon_clear(), fbcon_putc(), fbcon_clear_margins()
  *
  *  handles y values in range [0, scr_height-1] that correspond to real
  *  screen positions. y_wrap shift means that first line of bitmap may be
  *  anywhere on this display. These functions convert lineoffsets to
  *  bitmap offsets and deal with the wrap-around case by splitting blits.
  *
- *	fbcon_bmove_physical_8()    -- These functions fast implementations
  *	fbcon_clear_physical_8()    -- of original fbcon_XXX fns.
  *	fbcon_putc_physical_8()	    -- (font width != 8) may be added later
  *
@@ -1409,224 +1390,6 @@ static void fbcon_set_disp(struct fb_info *info, struct fb_var_screeninfo *var,
 	}
 }
 
-static __inline__ void ywrap_up(struct vc_data *vc, int count)
-{
-	struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
-	struct fbcon_ops *ops = info->fbcon_par;
-	struct fbcon_display *p = &fb_display[vc->vc_num];
-	
-	p->yscroll += count;
-	if (p->yscroll >= p->vrows)	/* Deal with wrap */
-		p->yscroll -= p->vrows;
-	ops->var.xoffset = 0;
-	ops->var.yoffset = p->yscroll * vc->vc_font.height;
-	ops->var.vmode |= FB_VMODE_YWRAP;
-	ops->update_start(info);
-	scrollback_max += count;
-	if (scrollback_max > scrollback_phys_max)
-		scrollback_max = scrollback_phys_max;
-	scrollback_current = 0;
-}
-
-static __inline__ void ywrap_down(struct vc_data *vc, int count)
-{
-	struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
-	struct fbcon_ops *ops = info->fbcon_par;
-	struct fbcon_display *p = &fb_display[vc->vc_num];
-	
-	p->yscroll -= count;
-	if (p->yscroll < 0)	/* Deal with wrap */
-		p->yscroll += p->vrows;
-	ops->var.xoffset = 0;
-	ops->var.yoffset = p->yscroll * vc->vc_font.height;
-	ops->var.vmode |= FB_VMODE_YWRAP;
-	ops->update_start(info);
-	scrollback_max -= count;
-	if (scrollback_max < 0)
-		scrollback_max = 0;
-	scrollback_current = 0;
-}
-
-static __inline__ void ypan_up(struct vc_data *vc, int count)
-{
-	struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
-	struct fbcon_display *p = &fb_display[vc->vc_num];
-	struct fbcon_ops *ops = info->fbcon_par;
-
-	p->yscroll += count;
-	if (p->yscroll > p->vrows - vc->vc_rows) {
-		ops->bmove(vc, info, p->vrows - vc->vc_rows,
-			    0, 0, 0, vc->vc_rows, vc->vc_cols);
-		p->yscroll -= p->vrows - vc->vc_rows;
-	}
-
-	ops->var.xoffset = 0;
-	ops->var.yoffset = p->yscroll * vc->vc_font.height;
-	ops->var.vmode &= ~FB_VMODE_YWRAP;
-	ops->update_start(info);
-	fbcon_clear_margins(vc, 1);
-	scrollback_max += count;
-	if (scrollback_max > scrollback_phys_max)
-		scrollback_max = scrollback_phys_max;
-	scrollback_current = 0;
-}
-
-static __inline__ void ypan_up_redraw(struct vc_data *vc, int t, int count)
-{
-	struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
-	struct fbcon_ops *ops = info->fbcon_par;
-	struct fbcon_display *p = &fb_display[vc->vc_num];
-
-	p->yscroll += count;
-
-	if (p->yscroll > p->vrows - vc->vc_rows) {
-		p->yscroll -= p->vrows - vc->vc_rows;
-		fbcon_redraw_move(vc, p, t + count, vc->vc_rows - count, t);
-	}
-
-	ops->var.xoffset = 0;
-	ops->var.yoffset = p->yscroll * vc->vc_font.height;
-	ops->var.vmode &= ~FB_VMODE_YWRAP;
-	ops->update_start(info);
-	fbcon_clear_margins(vc, 1);
-	scrollback_max += count;
-	if (scrollback_max > scrollback_phys_max)
-		scrollback_max = scrollback_phys_max;
-	scrollback_current = 0;
-}
-
-static __inline__ void ypan_down(struct vc_data *vc, int count)
-{
-	struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
-	struct fbcon_display *p = &fb_display[vc->vc_num];
-	struct fbcon_ops *ops = info->fbcon_par;
-	
-	p->yscroll -= count;
-	if (p->yscroll < 0) {
-		ops->bmove(vc, info, 0, 0, p->vrows - vc->vc_rows,
-			    0, vc->vc_rows, vc->vc_cols);
-		p->yscroll += p->vrows - vc->vc_rows;
-	}
-
-	ops->var.xoffset = 0;
-	ops->var.yoffset = p->yscroll * vc->vc_font.height;
-	ops->var.vmode &= ~FB_VMODE_YWRAP;
-	ops->update_start(info);
-	fbcon_clear_margins(vc, 1);
-	scrollback_max -= count;
-	if (scrollback_max < 0)
-		scrollback_max = 0;
-	scrollback_current = 0;
-}
-
-static __inline__ void ypan_down_redraw(struct vc_data *vc, int t, int count)
-{
-	struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
-	struct fbcon_ops *ops = info->fbcon_par;
-	struct fbcon_display *p = &fb_display[vc->vc_num];
-
-	p->yscroll -= count;
-
-	if (p->yscroll < 0) {
-		p->yscroll += p->vrows - vc->vc_rows;
-		fbcon_redraw_move(vc, p, t, vc->vc_rows - count, t + count);
-	}
-
-	ops->var.xoffset = 0;
-	ops->var.yoffset = p->yscroll * vc->vc_font.height;
-	ops->var.vmode &= ~FB_VMODE_YWRAP;
-	ops->update_start(info);
-	fbcon_clear_margins(vc, 1);
-	scrollback_max -= count;
-	if (scrollback_max < 0)
-		scrollback_max = 0;
-	scrollback_current = 0;
-}
-
-static void fbcon_redraw_move(struct vc_data *vc, struct fbcon_display *p,
-			      int line, int count, int dy)
-{
-	unsigned short *s = (unsigned short *)
-		(vc->vc_origin + vc->vc_size_row * line);
-
-	while (count--) {
-		unsigned short *start = s;
-		unsigned short *le = advance_row(s, 1);
-		unsigned short c;
-		int x = 0;
-		unsigned short attr = 1;
-
-		do {
-			c = scr_readw(s);
-			if (attr != (c & 0xff00)) {
-				attr = c & 0xff00;
-				if (s > start) {
-					fbcon_putcs(vc, start, s - start,
-						    dy, x);
-					x += s - start;
-					start = s;
-				}
-			}
-			console_conditional_schedule();
-			s++;
-		} while (s < le);
-		if (s > start)
-			fbcon_putcs(vc, start, s - start, dy, x);
-		console_conditional_schedule();
-		dy++;
-	}
-}
-
-static void fbcon_redraw_blit(struct vc_data *vc, struct fb_info *info,
-			struct fbcon_display *p, int line, int count, int ycount)
-{
-	int offset = ycount * vc->vc_cols;
-	unsigned short *d = (unsigned short *)
-	    (vc->vc_origin + vc->vc_size_row * line);
-	unsigned short *s = d + offset;
-	struct fbcon_ops *ops = info->fbcon_par;
-
-	while (count--) {
-		unsigned short *start = s;
-		unsigned short *le = advance_row(s, 1);
-		unsigned short c;
-		int x = 0;
-
-		do {
-			c = scr_readw(s);
-
-			if (c == scr_readw(d)) {
-				if (s > start) {
-					ops->bmove(vc, info, line + ycount, x,
-						   line, x, 1, s-start);
-					x += s - start + 1;
-					start = s + 1;
-				} else {
-					x++;
-					start++;
-				}
-			}
-
-			scr_writew(c, d);
-			console_conditional_schedule();
-			s++;
-			d++;
-		} while (s < le);
-		if (s > start)
-			ops->bmove(vc, info, line + ycount, x, line, x, 1,
-				   s-start);
-		console_conditional_schedule();
-		if (ycount > 0)
-			line++;
-		else {
-			line--;
-			/* NOTE: We subtract two lines from these pointers */
-			s -= vc->vc_size_row;
-			d -= vc->vc_size_row;
-		}
-	}
-}
-
 static void fbcon_redraw(struct vc_data *vc, struct fbcon_display *p,
 			 int line, int count, int offset)
 {
@@ -1687,7 +1450,6 @@ static bool fbcon_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
 {
 	struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
 	struct fbcon_display *p = &fb_display[vc->vc_num];
-	int scroll_partial = info->flags & FBINFO_PARTIAL_PAN_OK;
 
 	if (fbcon_is_inactive(vc, info))
 		return true;
@@ -1704,249 +1466,32 @@ static bool fbcon_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
 	case SM_UP:
 		if (count > vc->vc_rows)	/* Maximum realistic size */
 			count = vc->vc_rows;
-		if (logo_shown >= 0)
-			goto redraw_up;
-		switch (p->scrollmode) {
-		case SCROLL_MOVE:
-			fbcon_redraw_blit(vc, info, p, t, b - t - count,
-				     count);
-			fbcon_clear(vc, b - count, 0, count, vc->vc_cols);
-			scr_memsetw((unsigned short *) (vc->vc_origin +
-							vc->vc_size_row *
-							(b - count)),
-				    vc->vc_video_erase_char,
-				    vc->vc_size_row * count);
-			return true;
-
-		case SCROLL_WRAP_MOVE:
-			if (b - t - count > 3 * vc->vc_rows >> 2) {
-				if (t > 0)
-					fbcon_bmove(vc, 0, 0, count, 0, t,
-						    vc->vc_cols);
-				ywrap_up(vc, count);
-				if (vc->vc_rows - b > 0)
-					fbcon_bmove(vc, b - count, 0, b, 0,
-						    vc->vc_rows - b,
-						    vc->vc_cols);
-			} else if (info->flags & FBINFO_READS_FAST)
-				fbcon_bmove(vc, t + count, 0, t, 0,
-					    b - t - count, vc->vc_cols);
-			else
-				goto redraw_up;
-			fbcon_clear(vc, b - count, 0, count, vc->vc_cols);
-			break;
-
-		case SCROLL_PAN_REDRAW:
-			if ((p->yscroll + count <=
-			     2 * (p->vrows - vc->vc_rows))
-			    && ((!scroll_partial && (b - t == vc->vc_rows))
-				|| (scroll_partial
-				    && (b - t - count >
-					3 * vc->vc_rows >> 2)))) {
-				if (t > 0)
-					fbcon_redraw_move(vc, p, 0, t, count);
-				ypan_up_redraw(vc, t, count);
-				if (vc->vc_rows - b > 0)
-					fbcon_redraw_move(vc, p, b,
-							  vc->vc_rows - b, b);
-			} else
-				fbcon_redraw_move(vc, p, t + count, b - t - count, t);
-			fbcon_clear(vc, b - count, 0, count, vc->vc_cols);
-			break;
-
-		case SCROLL_PAN_MOVE:
-			if ((p->yscroll + count <=
-			     2 * (p->vrows - vc->vc_rows))
-			    && ((!scroll_partial && (b - t == vc->vc_rows))
-				|| (scroll_partial
-				    && (b - t - count >
-					3 * vc->vc_rows >> 2)))) {
-				if (t > 0)
-					fbcon_bmove(vc, 0, 0, count, 0, t,
-						    vc->vc_cols);
-				ypan_up(vc, count);
-				if (vc->vc_rows - b > 0)
-					fbcon_bmove(vc, b - count, 0, b, 0,
-						    vc->vc_rows - b,
-						    vc->vc_cols);
-			} else if (info->flags & FBINFO_READS_FAST)
-				fbcon_bmove(vc, t + count, 0, t, 0,
-					    b - t - count, vc->vc_cols);
-			else
-				goto redraw_up;
-			fbcon_clear(vc, b - count, 0, count, vc->vc_cols);
-			break;
-
-		case SCROLL_REDRAW:
-		      redraw_up:
-			fbcon_redraw(vc, p, t, b - t - count,
-				     count * vc->vc_cols);
-			fbcon_clear(vc, b - count, 0, count, vc->vc_cols);
-			scr_memsetw((unsigned short *) (vc->vc_origin +
-							vc->vc_size_row *
-							(b - count)),
-				    vc->vc_video_erase_char,
-				    vc->vc_size_row * count);
-			return true;
-		}
-		break;
+		fbcon_redraw(vc, p, t, b - t - count,
+			     count * vc->vc_cols);
+		fbcon_clear(vc, b - count, 0, count, vc->vc_cols);
+		scr_memsetw((unsigned short *) (vc->vc_origin +
+						vc->vc_size_row *
+						(b - count)),
+			    vc->vc_video_erase_char,
+			    vc->vc_size_row * count);
+		return true;
 
 	case SM_DOWN:
 		if (count > vc->vc_rows)	/* Maximum realistic size */
 			count = vc->vc_rows;
-		if (logo_shown >= 0)
-			goto redraw_down;
-		switch (p->scrollmode) {
-		case SCROLL_MOVE:
-			fbcon_redraw_blit(vc, info, p, b - 1, b - t - count,
-				     -count);
-			fbcon_clear(vc, t, 0, count, vc->vc_cols);
-			scr_memsetw((unsigned short *) (vc->vc_origin +
-							vc->vc_size_row *
-							t),
-				    vc->vc_video_erase_char,
-				    vc->vc_size_row * count);
-			return true;
-
-		case SCROLL_WRAP_MOVE:
-			if (b - t - count > 3 * vc->vc_rows >> 2) {
-				if (vc->vc_rows - b > 0)
-					fbcon_bmove(vc, b, 0, b - count, 0,
-						    vc->vc_rows - b,
-						    vc->vc_cols);
-				ywrap_down(vc, count);
-				if (t > 0)
-					fbcon_bmove(vc, count, 0, 0, 0, t,
-						    vc->vc_cols);
-			} else if (info->flags & FBINFO_READS_FAST)
-				fbcon_bmove(vc, t, 0, t + count, 0,
-					    b - t - count, vc->vc_cols);
-			else
-				goto redraw_down;
-			fbcon_clear(vc, t, 0, count, vc->vc_cols);
-			break;
-
-		case SCROLL_PAN_MOVE:
-			if ((count - p->yscroll <= p->vrows - vc->vc_rows)
-			    && ((!scroll_partial && (b - t == vc->vc_rows))
-				|| (scroll_partial
-				    && (b - t - count >
-					3 * vc->vc_rows >> 2)))) {
-				if (vc->vc_rows - b > 0)
-					fbcon_bmove(vc, b, 0, b - count, 0,
-						    vc->vc_rows - b,
-						    vc->vc_cols);
-				ypan_down(vc, count);
-				if (t > 0)
-					fbcon_bmove(vc, count, 0, 0, 0, t,
-						    vc->vc_cols);
-			} else if (info->flags & FBINFO_READS_FAST)
-				fbcon_bmove(vc, t, 0, t + count, 0,
-					    b - t - count, vc->vc_cols);
-			else
-				goto redraw_down;
-			fbcon_clear(vc, t, 0, count, vc->vc_cols);
-			break;
-
-		case SCROLL_PAN_REDRAW:
-			if ((count - p->yscroll <= p->vrows - vc->vc_rows)
-			    && ((!scroll_partial && (b - t == vc->vc_rows))
-				|| (scroll_partial
-				    && (b - t - count >
-					3 * vc->vc_rows >> 2)))) {
-				if (vc->vc_rows - b > 0)
-					fbcon_redraw_move(vc, p, b, vc->vc_rows - b,
-							  b - count);
-				ypan_down_redraw(vc, t, count);
-				if (t > 0)
-					fbcon_redraw_move(vc, p, count, t, 0);
-			} else
-				fbcon_redraw_move(vc, p, t, b - t - count, t + count);
-			fbcon_clear(vc, t, 0, count, vc->vc_cols);
-			break;
-
-		case SCROLL_REDRAW:
-		      redraw_down:
-			fbcon_redraw(vc, p, b - 1, b - t - count,
-				     -count * vc->vc_cols);
-			fbcon_clear(vc, t, 0, count, vc->vc_cols);
-			scr_memsetw((unsigned short *) (vc->vc_origin +
-							vc->vc_size_row *
-							t),
-				    vc->vc_video_erase_char,
-				    vc->vc_size_row * count);
-			return true;
-		}
+		fbcon_redraw(vc, p, b - 1, b - t - count,
+			     -count * vc->vc_cols);
+		fbcon_clear(vc, t, 0, count, vc->vc_cols);
+		scr_memsetw((unsigned short *) (vc->vc_origin +
+						vc->vc_size_row *
+						t),
+			    vc->vc_video_erase_char,
+			    vc->vc_size_row * count);
+		return true;
 	}
 	return false;
 }
 
-
-static void fbcon_bmove(struct vc_data *vc, int sy, int sx, int dy, int dx,
-			int height, int width)
-{
-	struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
-	struct fbcon_display *p = &fb_display[vc->vc_num];
-	
-	if (fbcon_is_inactive(vc, info))
-		return;
-
-	if (!width || !height)
-		return;
-
-	/*  Split blits that cross physical y_wrap case.
-	 *  Pathological case involves 4 blits, better to use recursive
-	 *  code rather than unrolled case
-	 *
-	 *  Recursive invocations don't need to erase the cursor over and
-	 *  over again, so we use fbcon_bmove_rec()
-	 */
-	fbcon_bmove_rec(vc, p, sy, sx, dy, dx, height, width,
-			p->vrows - p->yscroll);
-}
-
-static void fbcon_bmove_rec(struct vc_data *vc, struct fbcon_display *p, int sy, int sx,
-			    int dy, int dx, int height, int width, u_int y_break)
-{
-	struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
-	struct fbcon_ops *ops = info->fbcon_par;
-	u_int b;
-
-	if (sy < y_break && sy + height > y_break) {
-		b = y_break - sy;
-		if (dy < sy) {	/* Avoid trashing self */
-			fbcon_bmove_rec(vc, p, sy, sx, dy, dx, b, width,
-					y_break);
-			fbcon_bmove_rec(vc, p, sy + b, sx, dy + b, dx,
-					height - b, width, y_break);
-		} else {
-			fbcon_bmove_rec(vc, p, sy + b, sx, dy + b, dx,
-					height - b, width, y_break);
-			fbcon_bmove_rec(vc, p, sy, sx, dy, dx, b, width,
-					y_break);
-		}
-		return;
-	}
-
-	if (dy < y_break && dy + height > y_break) {
-		b = y_break - dy;
-		if (dy < sy) {	/* Avoid trashing self */
-			fbcon_bmove_rec(vc, p, sy, sx, dy, dx, b, width,
-					y_break);
-			fbcon_bmove_rec(vc, p, sy + b, sx, dy + b, dx,
-					height - b, width, y_break);
-		} else {
-			fbcon_bmove_rec(vc, p, sy + b, sx, dy + b, dx,
-					height - b, width, y_break);
-			fbcon_bmove_rec(vc, p, sy, sx, dy, dx, b, width,
-					y_break);
-		}
-		return;
-	}
-	ops->bmove(vc, info, real_y(p, sy), sx, real_y(p, dy), dx,
-		   height, width);
-}
-
 static void updatescrollmode(struct fbcon_display *p,
 					struct fb_info *info,
 					struct vc_data *vc)
@@ -2119,21 +1664,7 @@ static int fbcon_switch(struct vc_data *vc)
 
 	updatescrollmode(p, info, vc);
 
-	switch (p->scrollmode) {
-	case SCROLL_WRAP_MOVE:
-		scrollback_phys_max = p->vrows - vc->vc_rows;
-		break;
-	case SCROLL_PAN_MOVE:
-	case SCROLL_PAN_REDRAW:
-		scrollback_phys_max = p->vrows - 2 * vc->vc_rows;
-		if (scrollback_phys_max < 0)
-			scrollback_phys_max = 0;
-		break;
-	default:
-		scrollback_phys_max = 0;
-		break;
-	}
-
+	scrollback_phys_max = 0;
 	scrollback_max = 0;
 	scrollback_current = 0;