In the case we change the State from READY_TO_NULL the buffers in the pool
still hold an open dup file descriptor to the device, therefore the device
release function will not be called and the device will probably answer with
-EBUSY when we reopen it in the next NULL_TO_READY transition.
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
See bug #622500 and #612244.
It seems to cause strange occasional high latencies (almost 200ms) when dequeuing buffers from _buffer_alloc(). It is simpler and seems to work much better to dqbuf from the same thread that is queuing the next buffer.
This also does the following changes:
(1) pull the bufferpool code out into gstv4l2bufferpool.c, and make a
bit more generic so it can be used both for v4l2src and v4l2sink
(2) move some of the device probing/configuration/caps stuff into
gstv4l2object.c so it does not have to be duplicated between
v4l2src and v4l2sink
Fixes bug #590280.
