NAME

usba_hcdi_dup_isoc_req — duplicate an isochronous request

SYNOPSIS

#include <sys/usb/usba/hcdi.h>

usb_isoc_req_t *
usba_hcdi_dup_isoc_req(dev_info_t *dip, usb_isoc_req_t *usrp, usb_flags_t flags);

INTERFACE LEVEL

Volatile - illumos USB HCD private function

This is a private function that is not part of the stable DDI. It may be removed or changed at any time.

PARAMETERS

dip

A pointer to the HCD driver's dev_info structure.

usrp

A pointer to the USB isochronous request which will be duplicated.

flags

USB_FLAGS_NOSLEEP: Do not block waiting for memory. If memory is not available the allocation will fail.
USB_FLAGS_SLEEP: Perform a blocking allocation. If memory is not available, the function will wait until memory is made available.
Note, the request may still fail even if USB_FLAGS_SLEEP is specified.

DESCRIPTION

The usba_hcdi_dup_isoc_req() function is used to duplicate an existing isochronous request, usrp.

When the USBA framework initiates an isochronous in transfer with the usba_hcdi_pipe_isoc_xfer(9E) entry point, it is the HCD driver's responsibility to receive the periodic data from the pipe. When there is data available, the HCD must duplicate the original isochronous request and copy the available data into the request structure's isoc_data member, before handing over the request structure to the USBA framework by calling the usba_hcdi_cb(9F) function.

In addition to duplicating the request, it is the callers responsibility to increase the pipe handle's request count. For more information, see usba_hcdi_pipe_isoc_xfer(9E).

The dip argument should correspond to the HCD driver's dev_info_t structure. The usrp pointer should correspond to the initial isochronous request. The flags member must be appropriate for the context. If USB_FLAGS_SLEEP is passed while in interrupt context, then this function may fail.

CONTEXT

The usba_hcdi_dup_isoc_req() function may be called from user, kernel, or interrupt context; however, when in interrupt context, the value of flags must be USB_FLAGS_NOSLEEP.

RETURN VALUES

Upon successful completion, the usba_hcdi_dup_isoc_req() function returns a pointer to a duplicate isochronous request. Otherwise, NULL is returned to indicate that the request could not be duplicated.