EFI USB HC STATE

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Prototype

typedef enum {
  EfiUsbHcStateHalt,
  EfiUsbHcStateOperational,
  EfiUsbHcStateSuspend,
  EfiUsbHcStateMaximum
} EFI_USB_HC_STATE;

Values

Value Description
EfiUsbHcStateHalt The host controller is in halt state. No USB transactions can occur while in this state. The host controller can enter this state for three reasons:
  • After host controller hardware reset.
  • Explicitly set by software.
  • Triggered by a fatal error such as consistency check failure.
EfiUsbHcStateOperational The host controller is in an operational state. When in this state, the host controller can execute bus traffic. This state must be explicitly set to enable the USB bus traffic.
EfiUsbHcStateSuspend The host controller is in the suspend state. No USB transactions can occur while in this state. The host controller enters this state for the following reasons:
  • Explicitly set by software.
  • Triggered when there is no bus traffic for 3 microseconds.

Copyright (C) 2008 Phoenix Technologies Ltd. All Rights Reserved. Portions copyright (C) 2008 UEFI Forum, Inc. Used with permission.

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