usb_request_attributes(9S)Data Structures for Driverusb_request_attributes(9S)NAMEusb_request_attributes - Definition of USB request attributes
SYNOPSIS
#include <sys/usb/usba.h>
INTERFACE LEVEL
Solaris DDI specific (Solaris DDI)
DESCRIPTION
Request attributes specify how the USBA framework handles request exe‐
cution. Request attributes are specified in the request's *_attributes
field and belong to the enumerated type usb_req_attrs_t.
Supported request attributes are:
USB_ATTRS_SHORT_XFER_OK
Use this attribute when the maximum transfer size is known, but
it is possible for the request to receive a smaller amount of data.
This attribute tells the USBA framework to accept without error
transfers which are shorter than expected.
USB_ATTRS_PIPE_RESET
Have the USB framework reset the pipe automatically if an error
occurs during the transfer. Do not attempt to clear any stall. The
USB_CB_RESET_PIPE callback flag is passed to the client driver's
exception handler to show the pipe has been reset. Pending requests
on pipes which are reset are flushed unless the pipe is the default
pipe.
USB_ATTRS_AUTOCLEARING
Have the USB framework reset the pipe and clear functional stalls
automatically if an error occurs during the transfer. The callback
flags passed to the client driver's exception handler show the sta‐
tus after the attempt to clear the stall.
USB_CB_FUNCTIONAL_STALL is set in the callback flags to indicate
that a functional stall occurred. USB_CB_STALL_CLEARED is also set
if the stall is cleared. The default pipe never shows a functional
stall if the USB_ATTRS_AUTOCLEARING attribute is set. If
USB_CB_FUNCTIONAL_STALL is seen when autoclearing is enabled, the
device has a fatal error.
USB_CB_PROTOCOL_STALL is set without USB_CB_STALL_CLEARED in the
callback flags to indicate that a protocol stall was seen but was
not explicitly cleared. Protocol stalls are cleared automatically
when a subsequent command is issued.
Autoclearing a stalled default pipe is not allowed. The USB_CB_PRO‐
TOCOL_STALL callback flag is set in the callback flags to indicate
the default pipe is stalled.
Autoclearing is not allowed when the request is USB_REQ_GET_STATUS
on the default pipe.
USB_ATTRS_ONE_XFER
Applies only to interrupt-IN requests. Without this flag, inter‐
rupt-IN requests start periodic polling of the interrupt pipe. This
flag specifies to perform only a single transfer. Do not start
periodic transfers with this request.
USB_ATTRS_ISOC_START_FRAME
Applies only to isochronous requests and specifies that a request
be started at a given frame number. The starting frame number is
provided in the isoc_frame_no field of the usb_isoc_req_t. Please
see usb_isoc_request(9S) for more information about isochronous
requests.
USB_ATTRS_ISOC_START_FRAME can be used to delay a transfer by a few
frames, allowing transfers to an endpoint to sync up with another
source. (For example, synching up audio endpoints to a video
source.) The number of a suitable starting frame in the near future
can be found by adding an offset number of frames (usually between
four and ten) to the current frame number returned from
usb_get_current_frame_number(9F). Note that requests with starting
frames which have passed are rejected.
USB_ATTRS_ISOC_XFER_ASAP
Applies only to isochronous requests and specifies that a request
start as soon as possible. The host controller driver picks a
starting frame number which immediately follows the last frame of
the last queued request. The isoc_frame_no of the usb_isoc_req_t is
ignored. Please see usb_isoc_request(9S) for more information about
isochronous requests.
EXAMPLES
/*
* Allocate, initialize and issue a synchronous bulk-IN request.
* Allow for short transfers.
*/
struct buf *bp;
usb_bulk_req_t bulk_req;
mblk_t *mblk;
bulk_req = usb_alloc_bulk_req(dip, bp->b_bcount, USB_FLAGS_SLEEP);
bulk_req->bulk_attributes =
USB_ATTRS_AUTOCLEARING | USB_ATTRS_SHORT_XFER_OK;
if ((rval = usb_pipe_bulk_xfer(pipe, bulk_req, USB_FLAGS_SLEEP)) !=
USB_SUCCESS) {
cmn_err (CE_WARN, "%s%d: Error reading bulk data.",
ddi_driver_name(dip), ddi_get_instance(dip));
}
mblk = bulk_req->bulk_data;
bcopy(mblk->rptr, buf->b_un.b_addr, mblk->wptr - mblk->rptr);
bp->b_resid = bp->b_count - (mblk->wptr = mblk->rptr);
...
...
----
usb_pipe_handle_t handle;
usb_frame_number_t offset = 10;
usb_isoc_req_t *isoc_req;
isoc_req = usb_alloc_isoc_req(...);
...
...
isoc_req->isoc_frame_no = usb_get_current_frame_number(dip) + offset;
isoc_req->isoc_attributes = USB_ATTRS_ISOC_START_FRAME;
...
...
if (usb_pipe_isoc_xfer(handle, isoc_req, 0) != USB_SUCCESS) {
...
}
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Architecture │PCI-based systems │
├─────────────────────────────┼─────────────────────────────┤
│Interface stability │Evolving │
├─────────────────────────────┼─────────────────────────────┤
│Availability │SUNWusb, SUNWusbu │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOusb_alloc_request(9F), usb_get_current_frame_number(9F),
usb_pipe_bulk_xfer(9F), usb_pipe_ctrl_xfer(9F), usb_pipe_intr_xfer(9F),
usb_pipe_isoc_xfer(9F), usb_bulk_request(9S), usb_callback_flags(9S),
usb_ctrl_request(9S), usb_intr_request(9S), usb_isoc_request(9S),
usb_completion_reason(9S)SunOS 5.10 5 Jan 2004 usb_request_attributes(9S)
