fbcon: cursor blink control

Add sysfs attribute to enable or disable cursor blinking.  This will also
disable cursor blinking if the VT layer's softcursor is active.  These changes
are required to enable some machines to enter low-power states properly.
Signed-off-by: NAntonino Daplas <adaplas@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/video/console/fbcon.c

@@ -152,6 +152,7 @@ static int fbcon_set_origin(struct vc_data *);
 #define DEFAULT_CURSOR_BLINK_RATE	(20)
 
 static int vbl_cursor_cnt;
+static int fbcon_cursor_noblink;
 
 #define divides(a, b)	((!(a) || (b)%(a)) ? 0 : 1)
 
@@ -441,7 +442,8 @@ static void fbcon_add_cursor_timer(struct fb_info *info)
 	struct fbcon_ops *ops = info->fbcon_par;
 
 	if ((!info->queue.func || info->queue.func == fb_flashcursor) &&
-	    !(ops->flags & FBCON_FLAGS_CURSOR_TIMER)) {
+	    !(ops->flags & FBCON_FLAGS_CURSOR_TIMER) &&
+	    !fbcon_cursor_noblink) {
 		if (!info->queue.func)
 			INIT_WORK(&info->queue, fb_flashcursor);
 
@@ -1349,6 +1351,11 @@ static void fbcon_cursor(struct vc_data *vc, int mode)
 	if (fbcon_is_inactive(vc, info) || vc->vc_deccm != 1)
 		return;
 
+	if (vc->vc_cursor_type & 0x10)
+		fbcon_del_cursor_timer(info);
+	else
+		fbcon_add_cursor_timer(info);
+
 	ops->cursor_flash = (mode == CM_ERASE) ? 0 : 1;
 	if (mode & CM_SOFTBACK) {
 		mode &= ~CM_SOFTBACK;
@@ -3308,9 +3315,74 @@ static ssize_t show_rotate(struct class_device *class_device, char *buf)
 	return snprintf(buf, PAGE_SIZE, "%d\n", rotate);
 }
 
+static ssize_t show_cursor_blink(struct class_device *class_device, char *buf)
+{
+	struct fb_info *info;
+	struct fbcon_ops *ops;
+	int idx, blink = -1;
+
+	if (fbcon_has_exited)
+		return 0;
+
+	acquire_console_sem();
+	idx = con2fb_map[fg_console];
+
+	if (idx == -1 || registered_fb[idx] == NULL)
+		goto err;
+
+	info = registered_fb[idx];
+	ops = info->fbcon_par;
+
+	if (!ops)
+		goto err;
+
+	blink = (ops->flags & FBCON_FLAGS_CURSOR_TIMER) ? 1 : 0;
+err:
+	release_console_sem();
+	return snprintf(buf, PAGE_SIZE, "%d\n", blink);
+}
+
+static ssize_t store_cursor_blink(struct class_device *clas_device,
+				  const char *buf, size_t count)
+{
+	struct fb_info *info;
+	int blink, idx;
+	char **last = NULL;
+
+	if (fbcon_has_exited)
+		return count;
+
+	acquire_console_sem();
+	idx = con2fb_map[fg_console];
+
+	if (idx == -1 || registered_fb[idx] == NULL)
+		goto err;
+
+	info = registered_fb[idx];
+
+	if (!info->fbcon_par)
+		goto err;
+
+	blink = simple_strtoul(buf, last, 0);
+
+	if (blink) {
+		fbcon_cursor_noblink = 0;
+		fbcon_add_cursor_timer(info);
+	} else {
+		fbcon_cursor_noblink = 1;
+		fbcon_del_cursor_timer(info);
+	}
+
+err:
+	release_console_sem();
+	return count;
+}
+
 static struct class_device_attribute class_device_attrs[] = {
 	__ATTR(rotate, S_IRUGO|S_IWUSR, show_rotate, store_rotate),
 	__ATTR(rotate_all, S_IWUSR, NULL, store_rotate_all),
+	__ATTR(cursor_blink, S_IRUGO|S_IWUSR, show_cursor_blink,
+	       store_cursor_blink),
 };
 
 static int fbcon_init_class_device(void)