USB_CLEAR_HALT(9) USB Core APIs USB_CLEAR_HALT(9)NAMEusb_clear_halt - tells device to clear endpoint halt/stall condition
SYNOPSIS
int usb_clear_halt(struct usb_device * dev, int pipe);
ARGUMENTS
dev
device whose endpoint is halted
pipe
endpoint “pipe” being cleared
CONTEXT
!in_interrupt ()
DESCRIPTION
This is used to clear halt conditions for bulk and interrupt endpoints,
as reported by URB completion status. Endpoints that are halted are
sometimes referred to as being “stalled”. Such endpoints are unable to
transmit or receive data until the halt status is cleared. Any URBs
queued for such an endpoint should normally be unlinked by the driver
before clearing the halt condition, as described in sections 5.7.5 and
5.8.5 of the USB 2.0 spec.
Note that control and isochronous endpoints don´t halt, although
control endpoints report “protocol stall” (for unsupported requests)
using the same status code used to report a true stall.
This call is synchronous, and may not be used in an interrupt context.
Returns zero on success, or else the status code returned by the
underlying usb_control_msg call.
COPYRIGHTKernel Hackers Manual 2.6. November 2013 USB_CLEAR_HALT(9)
