Service_USB 32 - HUB state changed
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## Name

Service_USB 32 - HUB state changed — Broadcast by the Hub Class driver module to inform other programs about changes inside a hub or about changes about device states detected by the Hub.

## On Entry

R0 | 32 (reason code)
R1 | &80C00 (USB Service call)
R2 | Pointer to controller structure
R3 | Pointer to device structure (to Hub device)
R4 | Pointer to device structure (to device attached to port) or zero if not known
R5 | Port number or zero if not port but Hub related
R6 |
Value | Definition | Description
0 | SERVICE_USB_HUB_ATTACHED | Device has been attached to a port
1 | SERVICE_USB_HUB_REMOVED | Device has been removed from a port
2 | SERVICE_USB_HUB_DISABLED | Device has been disabled at a port
3 | SERVICE_USB_HUB_RESET | Device has been reset at a port
4 | SERVICE_USB_HUB_OC_OCCURED | Overcurrent Situation at Port/Hub occurred
5 | SERVICE_USB_HUB_OC_CLEARED | Overcurrent Situation at Port/Hub cleared

## On Exit

R0 | preserved
R1 | preserved to pass on (do not claim)
R2, R3, R4, R5, R6 | preserved

## Use

The events reported are based entirely on state changes detected by the devices. The Service Call is for information purposes only. You must not claim it.

### Warning

This Service call has been superseded and is no longer issued. The USB message system should now be used in preference.

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