USB HOST DRIVER V03 Freescale Semiconductor / Motorola, USB HOST DRIVER V03 Datasheet - Page 54

• Manufacturer Part Number: USB HOST DRIVER V03
• Description: USB Host Driver v03
• Manufacturer: Freescale Semiconductor / Motorola

3.6.9.
USB_LOCK_REQUEST
Definition:
typedef struct _USB_LOCK_REQUEST {
ULONG Flags;
} USB_LOCK_REQUEST, *PUSB_LOCK_REQUEST;
Members:
Flags
Specifies zero, one, or a combination of the following flags:
Acquires
USB_LOCK_DEVICE
Device lock. If there are no other handles to the same Device, the object maintains lock
and the Device object handle specified, becomes the owner of the lock. Otherwise the
request will be put in the queue by the Device lock queue and processed later. If the
application performs this request synchronously, the calling thread will be blocked until
the request is processed.
USB_TRY_LOCK_DEVICE
The request is the same as with specifying the USB_LOCK_DEVICE flag. However the
driver will not block the thread and put this request in the queue if the Device is already
locked, instead it returns with an error immediately.
USB_UNLOCK_DEVICE
Releases single Device lock by a given Device handle.
USB_TOTAL_UNLOCK
Releases all Device locks by a given Device handle.
Comments:
The structure is used by the
requests. It is possible to lock a
IOCTL_USB_LOCK_DEVICE
Device several times with the same handle. The Client should also release locks as often
as it acquires them. If the Client wants to remove all locks by a particular handle, it
should specify the USB_TOTAL_UNLOCK flag.
M
3-32
Programming Interface.
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE