usb_queue_reset_device - Reset a USB device from an atomic context
2. SYNOPSIS ▲
void usb_queue_reset_device(struct usb_interface * iface );
3. ARGUMENTS ▲
USB interface belonging to the device to reset
4. DESCRIPTION ▲
This function can be used to reset a USB device from an atomic context, where usb_reset_device wonAqt 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.
5. 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.
6. NOTE ▲
We donAqt 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.
7. COPYRIGHT ▲