[PATCH] Another batch of fbcon fixes

- Update display->vrows when fbset changes certain fields in var (such as
  color depth) but without changing the display resolution.  This might
  produce concommitant changes in other fields such as and especially
  var->yres_virtual.

- Clear the FBINFO_MISC_MODECHANGEUSER flag _before_ issuing a
  notifier_call_chain().  Clearing it after the notifier_call_chain() will
  cause fbcon to go into an infinite loop.

- Sanitized failure path of set_con2fb_map().
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/video/console/fbcon.c

@@ -326,30 +326,37 @@ int set_con2fb_map(int unit, int newidx)
 	struct vc_data *vc = vc_cons[unit].d;
 	int oldidx = con2fb_map[unit];
 	struct fb_info *info = registered_fb[newidx];
-	struct fb_info *oldinfo = registered_fb[oldidx];
+	struct fb_info *oldinfo = NULL;
 	int found;
 
+	if (oldidx == newidx)
+		return 0;
+
+	if (!vc)
+	    return -ENODEV;
+
 	if (!search_for_mapped_con()) {
 		info_idx = newidx;
 		fb_console_init();
 		return 0;
 	}
 
-	if (oldidx == newidx)
-		return 0;
-	if (!vc)
-	    return -ENODEV;
+	if (oldidx != -1)
+		oldinfo = registered_fb[oldidx];
+
 	found = search_fb_in_map(newidx);
 
 	acquire_console_sem();
 	con2fb_map[unit] = newidx;
 	if (!found) {
 		if (!try_module_get(info->fbops->owner)) {
+			con2fb_map[unit] = oldidx;
 			release_console_sem();
 			return -ENODEV;
 		}
 		if (info->fbops->fb_open && info->fbops->fb_open(info, 0)) {
 			module_put(info->fbops->owner);
+			con2fb_map[unit] = oldidx;
 			release_console_sem();
 			return -ENODEV;
 		}
@@ -360,18 +367,18 @@ int set_con2fb_map(int unit, int newidx)
 	 * fbcon should release it.
 	 */
 	if (oldinfo && !search_fb_in_map(oldidx)) {
-		int err;
-
-		if (info->queue.func == fb_flashcursor)
-			del_timer_sync(&oldinfo->cursor_timer);
-		if (oldinfo->fbops->fb_release) {
-			err = oldinfo->fbops->fb_release(oldinfo, 0);
-			if (err) {
+		if (oldinfo->fbops->fb_release &&
+		    oldinfo->fbops->fb_release(oldinfo, 0)) {
 			con2fb_map[unit] = oldidx;
+			if (!found && info->fbops->fb_release)
+				info->fbops->fb_release(info, 0);
+			if (!found)
+				module_put(info->fbops->owner);
 			release_console_sem();
-				return err;
-			}
+			return -ENODEV;
 		}
+		if (oldinfo->queue.func == fb_flashcursor)
+			del_timer_sync(&oldinfo->cursor_timer);
 		module_put(oldinfo->fbops->owner);
 	}
 	info->currcon = -1;
@@ -1624,8 +1631,10 @@ static void fbcon_bmove_rec(struct vc_data *vc, struct display *p, int sy, int s
 			height, width);
 }
 
-static __inline__ void updatescrollmode(struct display *p, struct fb_info *info, struct vc_data *vc)
+static __inline__ void updatescrollmode(struct display *p, struct fb_info *info,
+					struct vc_data *vc)
 {
+	int fh = vc->vc_font.height;
 	int cap = info->flags;
 	int good_pan = (cap & FBINFO_HWACCEL_YPAN)
 		 && divides(info->fix.ypanstep, vc->vc_font.height)
@@ -1636,6 +1645,13 @@ static __inline__ void updatescrollmode(struct display *p, struct fb_info *info,
 	int reading_fast = cap & FBINFO_READS_FAST;
 	int fast_copyarea = (cap & FBINFO_HWACCEL_COPYAREA) && !(cap & FBINFO_HWACCEL_DISABLED);
 
+	p->vrows = info->var.yres_virtual/fh;
+	if (info->var.yres > (fh * (vc->vc_rows + 1)))
+		p->vrows -= (info->var.yres - (fh * vc->vc_rows)) / fh;
+	if ((info->var.yres % fh) && (info->var.yres_virtual % fh <
+				      info->var.yres % fh))
+		p->vrows--;
+
 	if (good_wrap || good_pan) {
 		if (reading_fast || fast_copyarea)
 			p->scrollmode = good_wrap ? SCROLL_WRAP : SCROLL_PAN;
@@ -1686,11 +1702,6 @@ static int fbcon_resize(struct vc_data *vc, unsigned int width,
 		}
 		info->flags &= ~FBINFO_MISC_MODESWITCH;
 	}
-	p->vrows = var.yres_virtual/fh;
-	if (var.yres > (fh * (height + 1)))
-		p->vrows -= (var.yres - (fh * height)) / fh;
-	if ((var.yres % fh) && (var.yres_virtual % fh < var.yres % fh))
-		p->vrows--;
 	updatescrollmode(p, info, vc);
 	return 0;
 }
@@ -1766,7 +1777,6 @@ static int fbcon_switch(struct vc_data *vc)
 		struct fb_fillrect rect;
 		int bgshift = (vc->vc_hi_font_mask) ? 13 : 12;
 
-		logo_shown = fg_console;
 		rect.color = attr_bgcol_ec(bgshift, vc);
 		rect.rop = ROP_COPY;
 		rect.dx = rect.dy = 0;
@@ -2383,19 +2393,7 @@ static void fbcon_modechanged(struct fb_info *info)
 		cols = info->var.xres / vc->vc_font.width;
 		rows = info->var.yres / vc->vc_font.height;
 		vc_resize(vc->vc_num, cols, rows);
-		switch (p->scrollmode) {
-		case SCROLL_WRAP:
-			scrollback_phys_max = p->vrows - vc->vc_rows;
-			break;
-		case SCROLL_PAN:
-			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;
-		}
+		updatescrollmode(p, info, vc);
 		scrollback_max = 0;
 		scrollback_current = 0;
 		update_var(vc->vc_num, info);
@@ -2466,7 +2464,8 @@ static struct notifier_block fbcon_event_notifier = {
 };
 static int fbcon_event_notifier_registered;
 
-int __init fb_console_init(void)
+/* can't be __init as it can be called by set_con2fb_map() later */
+int fb_console_init(void)
 {
 	int err, i;
 

drivers/video/fbmem.c

@@ -999,9 +999,9 @@ fb_set_var(struct fb_info *info, struct fb_var_screeninfo *var)
 			fb_set_cmap(&info->cmap, 1, info);
 
 			if (info->flags & FBINFO_MISC_MODECHANGEUSER) {
+				info->flags &= ~FBINFO_MISC_MODECHANGEUSER;
 				notifier_call_chain(&fb_notifier_list,
 						    FB_EVENT_MODE_CHANGE, info);
-				info->flags &= ~FBINFO_MISC_MODECHANGEUSER;
 			}
 		}
 	}