ent this (all Linux
nodes are cycle master capable) while it also says that it "may" be
initialized by the bus manager or by the IRM standing in for a bus
manager.  (Neither Linux' firewire-core nor ieee1394 nodemgr implement
this.)

Since we cannot rely on Bus_Time having been initialized by a bus
manager, it is better to return an error instead of a nonsensical value
on a read request to Bus_Time.

Alternatively, we could fix the Bus_Time read integrity bug _and_
implement (a) cycle master's write support of the register as well as
(b) bus manager's Bus_Time initialization service, i.e. preservation of
the Bus_Time when the cycle master node of a bus changes.  However, that
would be quite some code for a feature that is unreliable to begin with
and very likely unused in practice.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
zŠ