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kIOFWMessagePowerStateChanged
Investigate FireWire power-state-change message at the first returning call, before a wrapper substitutes a generic message. This message reports a power-state transition that can invalidate assumptions about device availability or pending FireWire operations.
Read the status in context
IOKit results, internal tokens, and service messages cross user space, kernel services, and hardware families when diagnosing FireWire power-state-change message. Their integer representation does not make their control-flow roles interchangeable in an investigation of FireWire power-state-change message.
IOKit return values, internal tokens, and service messages share an integer representation but not the same control-flow meaning when diagnosing FireWire power-state-change message. Determine whether the API returns the value or delivers it as a message before treating it as failure in an investigation of FireWire power-state-change message. Keep the numeric value, declared return type, and first returning operation together with kIOFWMessagePowerStateChanged; the same integer can belong to a different status namespace in another API.
Diagnostic facts
| Capture | Diagnostic value |
|---|---|
| Old/new power state, device registry path, bus generation, sleep/wake timeline, and pending transactions. | Identifies the concrete object and operation associated with FireWire power-state-change message. |
| Numeric IOReturn/message value decoded with the matching SDK header while evaluating FireWire power-state-change message. | Separates argument or lifecycle state from the provider beneath FireWire power-state-change message. |
| Registry generation and first provider/client event before the result when diagnosing FireWire power-state-change message. | Creates a stable before-and-after comparison for FireWire power-state-change message. |
| Known-good device or service state on the same macOS/driver build in an investigation of FireWire power-state-change message. | Shows whether FireWire power-state-change message is the first result or a translated summary. |
For FireWire power-state-change message, preserve registry generation and first provider/client event before the result for the FireWire power-state-change message case before reinstalling, rebooting, clearing state, or substituting another device or provider. A success observed only after such a change is useful comparison data for FireWire power-state-change message, but it does not identify the original cause.
Verification path
- Suspend and resume a controlled device while tracing message order. Treat a changed result as a new boundary rather than automatic resolution of FireWire power-state-change message.
- Change one topology or lifecycle condition while keeping the request payload fixed while evaluating FireWire power-state-change message. Repeat the original supported operation so the check remains relevant to FireWire power-state-change message.
- Verify cleanup and object lifetime after the controlled operation when diagnosing FireWire power-state-change message. Keep unrelated inputs fixed so the change remains attributable to FireWire power-state-change message.
What the result does not prove
| Observed comparison | Next conclusion to test |
|---|---|
| The first control changes the result | Concentrate on the variable isolated by this check: Suspend and resume a controlled device while tracing message order. |
| The second comparison for FireWire power-state-change message reproduces the same first status | Preserve lower-layer provider, driver, service, or runtime evidence before editing application data. The second controlled check was: Change one topology or lifecycle condition while keeping the request payload fixed while evaluating FireWire power-state-change message. |
| A different status replaces FireWire power-state-change message after the bounded change | The operation moved to another boundary after the third controlled check. That check was: Verify cleanup and object lifetime after the controlled operation in an investigation of FireWire power-state-change message. Retain both results and interpret the replacement through its own API contract for FireWire power-state-change message. |
Closing the incident
Targeted correction. Pause submissions, rebuild state required after wake, and revalidate device generation before resuming. For FireWire power-state-change message, modify only the object, argument, policy, provider, or lifecycle state identified by the collected evidence.
Acceptance criterion. Sleep/wake cycles preserve data integrity and pending work is canceled or resumed by explicit policy. Re-run the original operation that produced FireWire power-state-change message under its original identity and supported configuration, then keep one negative control that still produces the expected neighboring outcome.
Technical references
These owner-maintained or standards-based sources define the namespace and subsystem contract needed to verify kIOFWMessagePowerStateChanged on the deployed platform version.
- Apple XNU: IOReturn definitions — defines the status namespace used for FireWire power-state-change message.
- Apple: IOKit documentation — documents the API or lifecycle boundary behind FireWire power-state-change message.
- Apple OSS: XNU source — provides ABI, implementation, or protocol context for FireWire power-state-change message.
- Apple XNU: FireWire family common definitions — supports the portability and verification limits for FireWire power-state-change message.
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