fbcon: set_con2fb_map fixes

set_con2fb_map() has regressed for some time.  Using fbcon=map:01, for
example, works only if there is only 1 working framebuffer. Trying to do a
set_con2fb_map() on a non-allocated vc will freeze the system.

- ensure that succeeding drivers after the first gets mapped to the console
- remove fbcon_preset_display() and modify fbcon_set_display() to include the
  former's functionality
- ensure that binding and unbinding succeeds if multiple drivers are mapped to
  the console

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>

1 files changed, 25 insertions, 39 deletions

diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index 7ba21eb1676c..13b67ee8b3c0 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -192,9 +192,7 @@ static __inline__ void ypan_down(struct vc_data *vc, int count);
 static void fbcon_bmove_rec(struct vc_data *vc, struct 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,
-                           struct vc_data *vc);
-static void fbcon_preset_disp(struct fb_info *info, struct fb_var_screeninfo *var,
-                              int unit);
+                           int unit);
 static void fbcon_redraw_move(struct vc_data *vc, struct display *p,
                               int line, int count, int dy);
 static void fbcon_modechanged(struct fb_info *info);
@@ -745,7 +743,9 @@ static int con2fb_acquire_newinfo(struct vc_data *vc, struct fb_info *info,
 
         if (!err) {
                 info->fbcon_par = ops;
-                set_blitting_type(vc, info);
+
+                if (vc)
+                        set_blitting_type(vc, info);
         }
 
         if (err) {
@@ -807,11 +807,7 @@ static void con2fb_init_display(struct vc_data *vc, struct fb_info *info,
 
         ops->flags |= FBCON_FLAGS_INIT;
         ops->graphics = 0;
-
-        if (vc)
-                fbcon_set_disp(info, &info->var, vc);
-        else
-                fbcon_preset_disp(info, &info->var, unit);
+        fbcon_set_disp(info, &info->var, unit);
 
         if (show_logo) {
                 struct vc_data *fg_vc = vc_cons[fg_console].d;
@@ -1116,6 +1112,9 @@ static void fbcon_init(struct vc_data *vc, int init)
         if (var_to_display(p, &info->var, info))
                 return;
 
+        if (!info->fbcon_par)
+                con2fb_acquire_newinfo(vc, info, vc->vc_num, -1);
+
         /* If we are not the first console on this
            fb, copy the font from that console */
         t = &fb_display[fg_console];
@@ -1382,36 +1381,29 @@ static int scrollback_phys_max = 0;
 static int scrollback_max = 0;
 static int scrollback_current = 0;
 
-/*
- * If no vc is existent yet, just set struct display
- */
-static void fbcon_preset_disp(struct fb_info *info, struct fb_var_screeninfo *var,
-                              int unit)
-{
-        struct display *p = &fb_display[unit];
-        struct display *t = &fb_display[fg_console];
-
-        if (var_to_display(p, var, info))
-                return;
-
-        p->fontdata = t->fontdata;
-        p->userfont = t->userfont;
-        if (p->userfont)
-                REFCOUNT(p->fontdata)++;
-}
-
 static void fbcon_set_disp(struct fb_info *info, struct fb_var_screeninfo *var,
-                           struct vc_data *vc)
+                           int unit)
 {
-        struct display *p = &fb_display[vc->vc_num], *t;
-        struct vc_data **default_mode = vc->vc_display_fg;
-        struct vc_data *svc = *default_mode;
+        struct display *p, *t;
+        struct vc_data **default_mode, *vc;
+        struct vc_data *svc;
         struct fbcon_ops *ops = info->fbcon_par;
         int rows, cols, charcnt = 256;
 
+        p = &fb_display[unit];
+
         if (var_to_display(p, var, info))
                 return;
+
+        vc = vc_cons[unit].d;
+
+        if (!vc)
+                return;
+
+        default_mode = vc->vc_display_fg;
+        svc = *default_mode;
         t = &fb_display[svc->vc_num];
+
         if (!vc->vc_font.data) {
                 vc->vc_font.data = (void *)(p->fontdata = t->fontdata);
                 vc->vc_font.width = (*default_mode)->vc_font.width;
@@ -3118,8 +3110,7 @@ static int fbcon_fb_registered(struct fb_info *info)
                         ret = fbcon_takeover(1);
         } else {
                 for (i = first_fb_vc; i <= last_fb_vc; i++) {
-                        if (con2fb_map_boot[i] == idx &&
-                            con2fb_map[i] == -1)
+                        if (con2fb_map_boot[i] == idx)
                                 set_con2fb_map(i, idx, 0);
                 }
         }
@@ -3167,12 +3158,7 @@ static void fbcon_new_modelist(struct fb_info *info)
                 mode = fb_find_nearest_mode(fb_display[i].mode,
                                             &info->modelist);
                 fb_videomode_to_var(&var, mode);
-
-                if (vc)
-                        fbcon_set_disp(info, &var, vc);
-                else
-                        fbcon_preset_disp(info, &var, i);
-
+                fbcon_set_disp(info, &var, vc->vc_num);
         }
 }