usb_queue_reset_device — Reset a USB device from an atomic context
void usb_queue_reset_device ( | struct usb_interface * iface); |
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.
- 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.
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.