USB_PIPE_GET_MAX_BULK_TRANSFER_SIZE(9F) Kernel Functions for Drivers

NAME

usb_pipe_get_max_bulk_transfer_size - Get maximum bulk transfer size

SYNOPSIS

#include <sys/usb/usba.h>


int usb_pipe_get_max_bulk_transfer_size(dev_info_t dip, size_t *size);

INTERFACE LEVEL

illumos DDI specific (illumos DDI)

PARAMETERS

dip
Pointer to the device's dev_info structure.


size
Returns the bulk transfer size.

DESCRIPTION

The usb_pipe_get_max_bulk_transfer_size() function returns the
maximum data transfer size in bytes that the host controller driver
can support per bulk request. This information can be used to limit
or break down larger requests to manageable sizes.

RETURN VALUES

USB_SUCCESS
Size is returned in size argument.


USB_INVALID_ARGS
dip and/or size argument is NULL.


USB_FAILURE
Size could not be returned. Zero is returned in
size arg.

CONTEXT

May be called from user, kernel or interrupt context.

EXAMPLES

int xxx_attach(dev_info_t *dip, int command)
{
...
usb_pipe_get_max_bulk_transfer_size(dip, &state>max_xfer_size);
...
}

void xxx_minphys(struct buf bp)
{
...
if (bp->b_bcount > state->max_xfer_size) {
bp->b_bcount = state->max_xfer_size;
}
...
}

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------+
|Architecture | PCI-based systems |
+--------------------+-------------------+
|Interface stability | Committed |
+--------------------+-------------------+

SEE ALSO

attributes(7), usb_alloc_request(9F), usb_pipe_bulk_xfer(9F),
usb_bulk_request(9S)

January 5, 2004
USB_PIPE_GET_MAX_BULK_TRANSFER_SIZE(9F)