Concurrent access to a single DVB CA 50221 interface slot is generally
discouraged. The underlying drivers (budget-av, budget-ci) do not implement
proper locking and thus two transactions could (and do) interfere with on
another.
This fixes the following problems seen by others and myself:
- sudden i/o errors when writing to the ci device which usually would
result in an undefined state of the hw and require a software restart
- errors about the CAM trying to send a buffer larger than the agreed size
usually also resulting in an undefined state of the hw
Due the to design of the DVB CA 50221 driver, implementing the locks in the
underlying drivers would not be enough and still leave some race conditions,
even though they were harder to trigger.
Signed-off-by: Matthias Dahl <devel@mortal-soul.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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