fbcon: delay the start of the cursor timer until a con_switch()

As reported in Bugzilla Bug 9093, upon switching to X, a small rectangular
cursor can still be seen blinking in the upper left part of the screen.  It is
fbcon's text cursor.  This is caused by a strange ioctl(..., KDSETMODE,
KD_TEXT) call done by something in userspace, perhaps by X itself, while the
tty is still in graphics mode.  And when the tty is in KD_TEXT mode, the
cursor timer is restarted.

Although this is a userspace problem, we can work around it by delaying the
restart of the cursor timer until an fbcon_switch() is called.  In other
words, the cursor timer will not be restarted even if a KD_TEXT mode switch is
requested.

Regression potential: Present but low

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 97a0224..0f32f4a 100644 (file)
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -2405,7 +2405,7 @@ static int fbcon_blank(struct vc_data *vc, int blank, int mode_switch)
                        update_screen(vc);
        }
 
-       if (fbcon_is_inactive(vc, info) ||
+       if (mode_switch || fbcon_is_inactive(vc, info) ||
            ops->blank_state != FB_BLANK_UNBLANK)
                fbcon_del_cursor_timer(info);
        else