USB HOST DRIVER V03 Freescale Semiconductor / Motorola, USB HOST DRIVER V03 Datasheet - Page 39

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

3.5.10. IOCTL_USB_LOCK_DEVICE
Locks access to the Device by a specified Device handle.
DeviceIoControl parameters:
lpInBuffer
Pointer to the buffer with
nInBufferSize
Must be equal to size of
lpOutBuffer
Not used with the operation. Must be NULL.
nOutBufferSize
Not used with the operation. Must be 0.
Comments:
By using this operation, the Client application can lock access to a particular Device,
preventing access by other Clients. This function locks the Device by means of the
Device handle. The Device handle specified in the request then becomes a master handle,
so that a request from any other Device handle will be blocked or returned with error.
Only access to those operations that change Device state or perform data transfers will be
blocked.
The request blocks the following operations on the Device:
ReadFile
be blocked or returned with error. The operation should be used when the Host software
allows different threads (processes) to share a single Device. In this case the request is
very useful to synchronize Device request transactions, for different Device and pipe
handle holders.
The Driver tracks the Device lock count, so that the caller must provide the same count of
unlock operations as for lock, until
M
IOCTL_USB_RESET_DEVICE
IOCTL_USB_UNCONFIGURE_DEVICE
IOCTL_USB_FEATURE_CONTROL
IOCTL_USB_CLASS_OR_VENDOR_REQUEST
IOCTL_USB_CYCLE_PORT
IOCTL_USB_RESET_PIPE
IOCTL_USB_SET_CONFIGURATION
IOCTL_USB_SET_INTERFACE
or
WriteFile
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
USB_LOCK_REQUEST
USB_LOCK_REQUEST
requests to pipe objects linked to different Device objects, will
Programming Interface.
USB_TOTAL_UNLOCK
structure.
structure.
flag is specified.
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