Fork us on GitHub Follow us on Facebook Follow us on Twitter

Changeset 79784ef8 in mainline


Ignore:
Timestamp:
2011-05-08T12:46:20Z (11 years ago)
Author:
Vojtech Horky <vojtechhorky@…>
Branches:
lfn, master
Children:
84de606d
Parents:
faf498d
Message:

Add comment how device "learns" its USB address

File:
1 edited

Legend:

Unmodified
Added
Removed
  • uspace/lib/drv/include/usb_iface.h

    rfaf498d r79784ef8  
    4949         * - arbitrary error code if returned by remote implementation
    5050         * - EOK - handle found, first parameter contains the USB address
     51         *
     52         * The handle must be the one used for binding USB address with
     53         * it (IPC_M_USBHC_BIND_ADDRESS), otherwise the host controller
     54         * (that this request would eventually reach) would not be able
     55         * to find it.
     56         * The problem is that this handle is actually assigned to the
     57         * function inside driver of the parent device (usually hub driver).
     58         * To bypass this problem, the initial caller specify handle as
     59         * zero and the first parent assigns the actual value.
     60         * See usb_iface_get_address_hub_child_impl() implementation
     61         * that could be assigned to device ops of a child device of in a
     62         * hub driver.
     63         * For example, the USB multi interface device driver (MID)
     64         * passes this initial zero without any modification because the
     65         * handle must be resolved by its parent.
    5166         */
    5267        IPC_M_USB_GET_ADDRESS,
Note: See TracChangeset for help on using the changeset viewer.