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kIOFireWireNoListenerOrTalker
A channel number alone does not create a stream
kIOFireWireNoListenerOrTalker indicates that an isochronous channel has no attached transmitting or receiving endpoint. Reserving a channel number and bandwidth is separate from creating the isochronous ports that actually send or receive media packets. Apple models those endpoints as talker and listener ports.
This status commonly points to setup or teardown ordering: a channel was started or queried before its ports were attached, or its final port was removed while code still expected an active stream. It differs from kIOFireWireMultipleTalkers, where there are too many senders, and from kIOFireWireNoChannels, where the resource manager cannot provide a channel at all.
Questions that identify the missing layer
- Was a talker or listener port successfully created and attached to this exact channel, in the current FireWire bus generation?
- Does the direction match the intended role? A capture path needs a listener; a transmit path needs a talker; a reservation without either role carries no isochronous traffic.
- Did cleanup release the last port before queued stream work completed, or did a reconnect path recreate the channel but omit the port attachment step?
- After a bus reset, confirm port and channel objects together. Restoring only the resource reservation is not enough to restore an application-level stream.
References
- Apple: IOFireWireIsochPortInterface
- Apple: IOFireWireRemoteIsochPortInterface
- Apple: FireWire Device Interface Guide — channel and endpoint model
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