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)

illumos January 5, 2004
USB_PIPE_GET_MAX_BULK_TRANSFER_SIZE(9F)