[linux-dvb] Reloading DVB drivers broken since 2.6.22, worked in 2.6.21

[Trent Piepho]

After a dvb card driver is unloaded and then loaded again, it is no longer
possible to access the dvr device.

Example:
cat /dev/dvb/adapter0/dvr0
  kill with ^C
rmmod cx88-dvb
modprobre cx88-dvb
cat /dev/dvb/adapter0/dvr0
cat: /dev/dvb/adapter0/dvr0: No such device

On kernel 2.6.21, this worked fine.  In order to get dvb working again,
it's necessary to unload and reload the dvb-core modules.

I strongly suspect commit 57861b432bda77f8bfafda2fb6f5a922d5f3aef1
is somehow related to this problem.