If we blank the panel by
echo 1 > /sys/devices/platform/omapfb/graphics/fb0/blank

Then, we reboot the sytem, the kernel will crash at
drivers/video/omap2/dss/core.c:323

This is because the panel is closed twice. Now check the state of a dssdev
to forbid a panel is power on or power off twice.
Signed-off-by: NStanley.Miao <stanley.miao@windriver.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@nokia.com>

Add a mutex_unlock missing on the error paths.  The use of the mutex is
balanced elsewhere in the file.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression E1;
@@

* mutex_lock(E1,...);
  <+... when != E1
  if (...) {
    ... when != E1
*   return ...;
  }
  ...+>
* mutex_unlock(E1,...);
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Acked-by: NMike Isely <isely@pobox.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

This is the panel used on Nokia N900
Signed-off-by: NRoger Quadros <roger.quadros@nokia.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@nokia.com>