usb_ep_set_halt(9)
NAME
usb_ep_set_halt - sets the endpoint halt feature.
SYNOPSIS
int usb_ep_set_halt(struct usb_ep * ep);
ARGUMENTS
- ep
- the non-isochronous endpoint being stalled
DESCRIPTION
Use this to stall an endpoint, perhaps as an error report. Except for
control endpoints, the endpoint stays halted (will not stream any data)
until the host clears this feature; drivers may need to empty the
endpoint´s request queue first, to make sure no inappropriate transfers
happen.
Note that while an endpoint CLEAR_FEATURE will be invisible to the
gadget driver, a SET_INTERFACE will not be. To reset endpoints for the
current altsetting, see usb_ep_clear_halt. When switching altsettings,
it´s simplest to use usb_ep_enable or usb_ep_disable for the endpoints.
Returns zero, or a negative error code. On success, this call sets
underlying hardware state that blocks data transfers. Attempts to halt
IN endpoints will fail (returning -EAGAIN) if any transfer requests are
still queued, or if the controller hardware (usually a FIFO) still
holds bytes that the host hasn´t collected.
AUTHOR
- David Brownell <dbrownell@users.sourceforge.net>
- Author.