gjdwebserver-overlay/sys-kernel/pinephone-sources/files/0203-revert-fbcon-remove-soft-scrollback-code.patch

--- b/drivers/video/fbdev/core/fbcon.c
+++ a/drivers/video/fbdev/core/fbcon.c
@@ -124,6 +124,12 @@ static int logo_lines;
 /* logo_shown is an index to vc_cons when >= 0; otherwise follows FBCON_LOGO
    enums.  */
 static int logo_shown = FBCON_LOGO_CANSHOW;
+/* Software scrollback */
+static int fbcon_softback_size = 32768;
+static unsigned long softback_buf, softback_curr;
+static unsigned long softback_in;
+static unsigned long softback_top, softback_end;
+static int softback_lines;
 /* console mappings */
 static unsigned int first_fb_vc;
 static unsigned int last_fb_vc = MAX_NR_CONSOLES - 1;
@@ -163,6 +169,8 @@ static int margin_color;
 
 static const struct consw fb_con;
 
+#define CM_SOFTBACK	(8)
+
 #define advance_row(p, delta) (unsigned short *)((unsigned long)(p) + (delta) * vc->vc_size_row)
 
 static int fbcon_set_origin(struct vc_data *);
@@ -347,6 +355,18 @@ static int get_color(struct vc_data *vc,
 	return color;
 }
 
+static void fbcon_update_softback(struct vc_data *vc)
+{
+	int l = fbcon_softback_size / vc->vc_size_row;
+
+	if (l > 5)
+		softback_end = softback_buf + l * vc->vc_size_row;
+	else
+		/* Smaller scrollback makes no sense, and 0 would screw
+		   the operation totally */
+		softback_top = 0;
+}
+
 static void fb_flashcursor(struct work_struct *work)
 {
 	struct fbcon_ops *ops = container_of(work, struct fbcon_ops, cursor_work.work);
@@ -379,7 +399,7 @@ static void fb_flashcursor(struct work_s
 	c = scr_readw((u16 *) vc->vc_pos);
 	mode = (!ops->cursor_flash || ops->cursor_state.enable) ?
 		CM_ERASE : CM_DRAW;
-	ops->cursor(vc, info, mode, 0, get_color(vc, info, c, 1),
+	ops->cursor(vc, info, mode, softback_lines, get_color(vc, info, c, 1),
 		    get_color(vc, info, c, 0));
 	console_unlock();
 
@@ -419,7 +439,13 @@ static int __init fb_console_setup(char
 		}
 		
 		if (!strncmp(options, "scrollback:", 11)) {
-			pr_warn("Ignoring scrollback size option\n");
+			options += 11;
+			if (*options) {
+				fbcon_softback_size = simple_strtoul(options, &options, 0);
+				if (*options == 'k' || *options == 'K') {
+					fbcon_softback_size *= 1024;
+				}
+			}
 			continue;
 		}
 		
@@ -959,6 +985,31 @@ static const char *fbcon_startup(void)
 
 	set_blitting_type(vc, info);
 
+	if (info->fix.type != FB_TYPE_TEXT) {
+		if (fbcon_softback_size) {
+			if (!softback_buf) {
+				softback_buf =
+				    (unsigned long)
+				    kvmalloc(fbcon_softback_size,
+					    GFP_KERNEL);
+				if (!softback_buf) {
+					fbcon_softback_size = 0;
+					softback_top = 0;
+				}
+			}
+		} else {
+			if (softback_buf) {
+				kvfree((void *) softback_buf);
+				softback_buf = 0;
+				softback_top = 0;
+			}
+		}
+		if (softback_buf)
+			softback_in = softback_top = softback_curr =
+			    softback_buf;
+		softback_lines = 0;
+	}
+
 	/* Setup default font */
 	if (!p->fontdata && !vc->vc_font.data) {
 		if (!fontname[0] || !(font = find_font(fontname)))
@@ -1129,6 +1180,9 @@ static void fbcon_init(struct vc_data *v
 	if (logo)
 		fbcon_prepare_logo(vc, info, cols, rows, new_cols, new_rows);
 
+	if (vc == svc && softback_buf)
+		fbcon_update_softback(vc);
+
 	if (ops->rotate_font && ops->rotate_font(info, vc)) {
 		ops->rotate = FB_ROTATE_UR;
 		set_blitting_type(vc, info);
@@ -1152,6 +1206,9 @@ static void fbcon_release_all(void)
 	struct fb_info *info;
 	int i, j, mapped;
 
+	kvfree((void *)softback_buf);
+	softback_buf = 0UL;
+
 	fbcon_for_each_registered_fb(i) {
 		mapped = 0;
 		info = fbcon_registered_fb[i];
@@ -1312,6 +1369,7 @@ static void fbcon_cursor(struct vc_data
 {
 	struct fb_info *info = fbcon_info_from_console(vc->vc_num);
 	struct fbcon_ops *ops = info->fbcon_par;
+	int y;
  	int c = scr_readw((u16 *) vc->vc_pos);
 
 	ops->cur_blink_jiffies = msecs_to_jiffies(vc->vc_cur_blink_ms);
@@ -1325,11 +1383,19 @@ static void fbcon_cursor(struct vc_data
 		fbcon_add_cursor_work(info);
 
 	ops->cursor_flash = (mode == CM_ERASE) ? 0 : 1;
+	if (mode & CM_SOFTBACK) {
+		mode &= ~CM_SOFTBACK;
+		y = softback_lines;
+	} else {
+		if (softback_lines)
+			fbcon_set_origin(vc);
+		y = 0;
+	}
 
 	if (!ops->cursor)
 		return;
 
-	ops->cursor(vc, info, mode, 0, get_color(vc, info, c, 1),
+	ops->cursor(vc, info, mode, y, get_color(vc, info, c, 1),
 		    get_color(vc, info, c, 0));
 }
 
@@ -1399,6 +1465,8 @@ static void fbcon_set_disp(struct fb_inf
 
 	if (con_is_visible(vc)) {
 		update_screen(vc);
+		if (softback_buf)
+			fbcon_update_softback(vc);
 	}
 }
 
@@ -1536,6 +1604,99 @@ static __inline__ void ypan_down_redraw(
 	scrollback_current = 0;
 }
 
+static void fbcon_redraw_softback(struct vc_data *vc, struct fbcon_display *p,
+				  long delta)
+{
+	int count = vc->vc_rows;
+	unsigned short *d, *s;
+	unsigned long n;
+	int line = 0;
+
+	d = (u16 *) softback_curr;
+	if (d == (u16 *) softback_in)
+		d = (u16 *) vc->vc_origin;
+	n = softback_curr + delta * vc->vc_size_row;
+	softback_lines -= delta;
+	if (delta < 0) {
+		if (softback_curr < softback_top && n < softback_buf) {
+			n += softback_end - softback_buf;
+			if (n < softback_top) {
+				softback_lines -=
+				    (softback_top - n) / vc->vc_size_row;
+				n = softback_top;
+			}
+		} else if (softback_curr >= softback_top
+			   && n < softback_top) {
+			softback_lines -=
+			    (softback_top - n) / vc->vc_size_row;
+			n = softback_top;
+		}
+	} else {
+		if (softback_curr > softback_in && n >= softback_end) {
+			n += softback_buf - softback_end;
+			if (n > softback_in) {
+				n = softback_in;
+				softback_lines = 0;
+			}
+		} else if (softback_curr <= softback_in && n > softback_in) {
+			n = softback_in;
+			softback_lines = 0;
+		}
+	}
+	if (n == softback_curr)
+		return;
+	softback_curr = n;
+	s = (u16 *) softback_curr;
+	if (s == (u16 *) softback_in)
+		s = (u16 *) vc->vc_origin;
+	while (count--) {
+		unsigned short *start;
+		unsigned short *le;
+		unsigned short c;
+		int x = 0;
+		unsigned short attr = 1;
+
+		start = s;
+		le = advance_row(s, 1);
+		do {
+			c = scr_readw(s);
+			if (attr != (c & 0xff00)) {
+				attr = c & 0xff00;
+				if (s > start) {
+					fbcon_putcs(vc, start, s - start,
+						    line, x);
+					x += s - start;
+					start = s;
+				}
+			}
+			if (c == scr_readw(d)) {
+				if (s > start) {
+					fbcon_putcs(vc, start, s - start,
+						    line, x);
+					x += s - start + 1;
+					start = s + 1;
+				} else {
+					x++;
+					start++;
+				}
+			}
+			s++;
+			d++;
+		} while (s < le);
+		if (s > start)
+			fbcon_putcs(vc, start, s - start, line, x);
+		line++;
+		if (d == (u16 *) softback_end)
+			d = (u16 *) softback_buf;
+		if (d == (u16 *) softback_in)
+			d = (u16 *) vc->vc_origin;
+		if (s == (u16 *) softback_end)
+			s = (u16 *) softback_buf;
+		if (s == (u16 *) softback_in)
+			s = (u16 *) vc->vc_origin;
+	}
+}
+
 static void fbcon_redraw_move(struct vc_data *vc, struct fbcon_display *p,
 			      int line, int count, int dy)
 {
@@ -1740,6 +1901,31 @@ static void fbcon_bmove(struct vc_data *
 			p->vrows - p->yscroll);
 }
 
+static inline void fbcon_softback_note(struct vc_data *vc, int t,
+				       int count)
+{
+	unsigned short *p;
+
+	if (vc->vc_num != fg_console)
+		return;
+	p = (unsigned short *) (vc->vc_origin + t * vc->vc_size_row);
+
+	while (count) {
+		scr_memcpyw((u16 *) softback_in, p, vc->vc_size_row);
+		count--;
+		p = advance_row(p, 1);
+		softback_in += vc->vc_size_row;
+		if (softback_in == softback_end)
+			softback_in = softback_buf;
+		if (softback_in == softback_top) {
+			softback_top += vc->vc_size_row;
+			if (softback_top == softback_end)
+				softback_top = softback_buf;
+		}
+	}
+	softback_curr = softback_in;
+}
+
 static bool fbcon_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
 		enum con_scroll dir, unsigned int count)
 {
@@ -1762,6 +1948,8 @@ static bool fbcon_scroll(struct vc_data
 	case SM_UP:
 		if (count > vc->vc_rows)	/* Maximum realistic size */
 			count = vc->vc_rows;
+		if (softback_top)
+			fbcon_softback_note(vc, t, count);
 		switch (fb_scrollmode(p)) {
 		case SCROLL_MOVE:
 			fbcon_redraw_blit(vc, info, p, t, b - t - count,
@@ -2076,6 +2264,14 @@ static int fbcon_switch(struct vc_data *
 	info = fbcon_info_from_console(vc->vc_num);
 	ops = info->fbcon_par;
 
+	if (softback_top) {
+		if (softback_lines)
+			fbcon_set_origin(vc);
+		softback_top = softback_curr = softback_in = softback_buf;
+		softback_lines = 0;
+		fbcon_update_softback(vc);
+	}
+
 	if (logo_shown >= 0) {
 		struct vc_data *conp2 = vc_cons[logo_shown].d;
 
@@ -2406,6 +2602,9 @@ static int fbcon_do_set_font(struct vc_d
 	int resize;
 	char *old_data = NULL;
 
+	if (con_is_visible(vc) && softback_lines)
+		fbcon_set_origin(vc);
+
 	resize = (w != vc->vc_font.width) || (h != vc->vc_font.height);
 	if (p->userfont)
 		old_data = vc->vc_font.data;
@@ -2436,6 +2635,8 @@ static int fbcon_do_set_font(struct vc_d
 		ret = vc_resize(vc, cols, rows);
 		if (ret)
 			goto err_out;
+		if (con_is_visible(vc) && softback_buf)
+			fbcon_update_softback(vc);
 	} else if (con_is_visible(vc)
 		   && vc->vc_mode == KD_TEXT) {
 		fbcon_clear_margins(vc, 0);
@@ -2582,7 +2783,19 @@ static void fbcon_set_palette(struct vc_
 
 static u16 *fbcon_screen_pos(const struct vc_data *vc, int offset)
 {
-	return (u16 *) (vc->vc_origin + offset);
+	unsigned long p;
+	int line;
+	
+	if (vc->vc_num != fg_console || !softback_lines)
+		return (u16 *) (vc->vc_origin + offset);
+	line = offset / vc->vc_size_row;
+	if (line >= softback_lines)
+		return (u16 *) (vc->vc_origin + offset -
+				softback_lines * vc->vc_size_row);
+	p = softback_curr + offset;
+	if (p >= softback_end)
+		p += softback_buf - softback_end;
+	return (u16 *) p;
 }
 
 static unsigned long fbcon_getxy(struct vc_data *vc, unsigned long pos,
@@ -2596,7 +2809,22 @@ static unsigned long fbcon_getxy(struct
 
 		x = offset % vc->vc_cols;
 		y = offset / vc->vc_cols;
+		if (vc->vc_num == fg_console)
+			y += softback_lines;
+		ret = pos + (vc->vc_cols - x) * 2;
+	} else if (vc->vc_num == fg_console && softback_lines) {
+		unsigned long offset = pos - softback_curr;
+
+		if (pos < softback_curr)
+			offset += softback_end - softback_buf;
+		offset /= 2;
+		x = offset % vc->vc_cols;
+		y = offset / vc->vc_cols;
 		ret = pos + (vc->vc_cols - x) * 2;
+		if (ret == softback_end)
+			ret = softback_buf;
+		if (ret == softback_in)
+			ret = vc->vc_origin;
 	} else {
 		/* Should not happen */
 		x = y = 0;
@@ -2624,11 +2852,106 @@ static void fbcon_invert_region(struct v
 			a = ((a) & 0x88ff) | (((a) & 0x7000) >> 4) |
 			    (((a) & 0x0700) << 4);
 		scr_writew(a, p++);
+		if (p == (u16 *) softback_end)
+			p = (u16 *) softback_buf;
+		if (p == (u16 *) softback_in)
+			p = (u16 *) vc->vc_origin;
+	}
+}
+
+static void fbcon_scrolldelta(struct vc_data *vc, int lines)
+{
+	struct fb_info *info = registered_fb[con2fb_map[fg_console]];
+	struct fbcon_ops *ops = info->fbcon_par;
+	struct fbcon_display *disp = &fb_display[fg_console];
+	int offset, limit, scrollback_old;
+
+	if (softback_top) {
+		if (vc->vc_num != fg_console)
+			return;
+		if (vc->vc_mode != KD_TEXT || !lines)
+			return;
+		if (logo_shown >= 0) {
+			struct vc_data *conp2 = vc_cons[logo_shown].d;
+
+			if (conp2->vc_top == logo_lines
+			    && conp2->vc_bottom == conp2->vc_rows)
+				conp2->vc_top = 0;
+			if (logo_shown == vc->vc_num) {
+				unsigned long p, q;
+				int i;
+
+				p = softback_in;
+				q = vc->vc_origin +
+				    logo_lines * vc->vc_size_row;
+				for (i = 0; i < logo_lines; i++) {
+					if (p == softback_top)
+						break;
+					if (p == softback_buf)
+						p = softback_end;
+					p -= vc->vc_size_row;
+					q -= vc->vc_size_row;
+					scr_memcpyw((u16 *) q, (u16 *) p,
+						    vc->vc_size_row);
+				}
+				softback_in = softback_curr = p;
+				update_region(vc, vc->vc_origin,
+					      logo_lines * vc->vc_cols);
+			}
+			logo_shown = FBCON_LOGO_CANSHOW;
+		}
+		fbcon_cursor(vc, CM_ERASE | CM_SOFTBACK);
+		fbcon_redraw_softback(vc, disp, lines);
+		fbcon_cursor(vc, CM_DRAW | CM_SOFTBACK);
+		return;
 	}
+
+	if (!scrollback_phys_max)
+		return;
+
+	scrollback_old = scrollback_current;
+	scrollback_current -= lines;
+	if (scrollback_current < 0)
+		scrollback_current = 0;
+	else if (scrollback_current > scrollback_max)
+		scrollback_current = scrollback_max;
+	if (scrollback_current == scrollback_old)
+		return;
+
+	if (fbcon_is_inactive(vc, info))
+		return;
+
+	fbcon_cursor(vc, CM_ERASE);
+
+	offset = disp->yscroll - scrollback_current;
+	limit = disp->vrows;
+	switch (disp->scrollmode) {
+	case SCROLL_WRAP_MOVE:
+		info->var.vmode |= FB_VMODE_YWRAP;
+		break;
+	case SCROLL_PAN_MOVE:
+	case SCROLL_PAN_REDRAW:
+		limit -= vc->vc_rows;
+		info->var.vmode &= ~FB_VMODE_YWRAP;
+		break;
+	}
+	if (offset < 0)
+		offset += limit;
+	else if (offset >= limit)
+		offset -= limit;
+
+	ops->var.xoffset = 0;
+	ops->var.yoffset = offset * vc->vc_font.height;
+	ops->update_start(info);
+
+	if (!scrollback_current)
+		fbcon_cursor(vc, CM_DRAW);
 }
 
 static int fbcon_set_origin(struct vc_data *vc)
 {
+	if (softback_lines)
+		fbcon_scrolldelta(vc, softback_lines);
 	return 0;
 }
 
@@ -2692,6 +3015,8 @@ static void fbcon_modechanged(struct fb_
 
 		fbcon_set_palette(vc, color_table);
 		update_screen(vc);
+		if (softback_buf)
+			fbcon_update_softback(vc);
 	}
 }
 
@@ -3154,6 +3479,7 @@ static const struct consw fb_con = {
 	.con_font_get 		= fbcon_get_font,
 	.con_font_default	= fbcon_set_def_font,
 	.con_set_palette 	= fbcon_set_palette,
+	.con_scrolldelta 	= fbcon_scrolldelta,
 	.con_set_origin 	= fbcon_set_origin,
 	.con_invert_region 	= fbcon_invert_region,
 	.con_screen_pos 	= fbcon_screen_pos,