Messages in this thread | | | Date | Sat, 26 Dec 2009 15:33:16 +0100 | From | Stefan Richter <> | Subject | Re: [PATCH 1/5] firewire: fix use of multiple AV/C devices, allow multiple FCP listeners |
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Stefan Richter wrote: > BTW, what about AV/C RESERVE? According to the spec, it means that a > controller gets exclusive FCP access to a target. At this point, a > node-wide FCP serializer will have to decide on a policy:
(because the spec does not have a concept of reservation IDs. It stupidly takes node IDs for what should be reservation IDs even though it distinguishes between the concepts of 'controller' and 'node'.)
> The simpler policy would be to remain oblivious of RESERVE. The more > difficult to implement policy would be to keep track of reservations > and only allow a single controller process (or user, or...) to perform > subsequent transactions for the duration of a reservation.
Err, no, forget that. A reservation prevents only control commands, but AFAIU not even all control commands because subunit specifications may enumerate control commands that are still allowed during a reservation. So the serializer would have to have knowledge of subunit specs. That would quickly get out of hand.
> (I for one would keep it simple.) -- Stefan Richter -=====-==--= ==-- ==-=- http://arcgraph.de/sr/
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