USB_QUEUE_RESET_DEVI(9) USB Core APIs USB_QUEUE_RESET_DEVI(9)
NAME
usb_queue_reset_device - Reset a USB device from an atomic context
SYNOPSIS
void usb_queue_reset_device(struct usb_interface * iface);
ARGUMENTS
iface
USB interface belonging to the device to reset
DESCRIPTION
This function can be used to reset a USB device from an atomic context, where usb_reset_device won't work (as it blocks).
Doing a reset via this method is functionally equivalent to calling usb_reset_device, except for the fact that it is delayed to a
workqueue. This means that any drivers bound to other interfaces might be unbound, as well as users from usbfs in user space.
CORNER CASES
- Scheduling two resets at the same time from two different drivers attached to two different interfaces of the same device is possible;
depending on how the driver attached to each interface handles ->pre_reset, the second reset might happen or not.
- If a driver is unbound and it had a pending reset, the reset will be cancelled.
- This function can be called during .probe or .disconnect times. On return from .disconnect, any pending resets will be cancelled.
There is no no need to lock/unlock the reset_ws as schedule_work does its own.
NOTE
We don't do any reference count tracking because it is not needed. The lifecycle of the work_struct is tied to the usb_interface. Before
destroying the interface we cancel the work_struct, so the fact that work_struct is queued and or running means the interface (and thus,
the device) exist and are referenced.
COPYRIGHT
Kernel Hackers Manual 2.6. July 2010 USB_QUEUE_RESET_DEVI(9)
