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# StartIO

Tells the device to start IO.

```
virtual kern_return_t StartIO(IOUserVideoStartStopFlags in_flags);
```

## Parameters

`in_flags`

An IOUserVideoStartStopFlags value that indicates how IO is starting.

## Return Value

A kern_return_t value indicating whether IO started successfully.

## Discussion

The default implementation always returns `kIOReturnSuccess`.
Subclass and override this method to handle any hardware-specific things when IO is starting. Then
call the superclass implementation to update IO state.
This call always completes with a definitive success or failure result. The hardware can take as long
as necessary such that it always either succeeds (and returns `kIOReturnSuccess`) or fails.
The system also calls StartIO for all streams added to the device.

---

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