fbcon: smart blitter usage for scrolling

This patch replaces the current SCROLL_MOVE method with smarter method using
the same logic as the SCROLL_REDRAW method.  This brings these two methods
much closer in performance and benefits all framebuffers which uses the
SCROLL_MOVE method.

[adaplas]
- remove unnecessary char attribute checking
- whitespace cleanups and 80-column line fixes

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index 73813c6..7888e31 100644 (file)
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -1704,6 +1704,56 @@ static void fbcon_redraw_move(struct vc_data *vc, struct display *p,
        }
 }
 
+static void fbcon_redraw_blit(struct vc_data *vc, struct fb_info *info,
+                       struct 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 display *p,
                         int line, int count, int offset)
 {
@@ -1789,7 +1839,6 @@ static int fbcon_scroll(struct vc_data *vc, int t, int b, int dir,
 {
        struct fb_info *info = registered_fb[con2fb_map[vc->vc_num]];
        struct display *p = &fb_display[vc->vc_num];
-       struct fbcon_ops *ops = info->fbcon_par;
        int scroll_partial = info->flags & FBINFO_PARTIAL_PAN_OK;
 
        if (fbcon_is_inactive(vc, info))
@@ -1813,10 +1862,15 @@ static int fbcon_scroll(struct vc_data *vc, int t, int b, int dir,
                        goto redraw_up;
                switch (p->scrollmode) {
                case SCROLL_MOVE:
-                       ops->bmove(vc, info, t + count, 0, t, 0,
-                                   b - t - count, vc->vc_cols);
-                       ops->clear(vc, info, b - count, 0, count,
-                                 vc->vc_cols);
+                       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 1;
                        break;
 
                case SCROLL_WRAP_MOVE:
@@ -1899,9 +1953,15 @@ static int fbcon_scroll(struct vc_data *vc, int t, int b, int dir,
                        goto redraw_down;
                switch (p->scrollmode) {
                case SCROLL_MOVE:
-                       ops->bmove(vc, info, t, 0, t + count, 0,
-                                   b - t - count, vc->vc_cols);
-                       ops->clear(vc, info, t, 0, count, vc->vc_cols);
+                       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 1;
                        break;
 
                case SCROLL_WRAP_MOVE: