#ident	"@(#)ddi_intr_set_nreq.9f 1.1     08/09/30 SMI"

Kernel Functions for Device Drivers		ddi_intr_set_nreq(9F)

NAME
    ddi_intr_set_nreq - set the number of interrupts requested for
    a device driver instance

SYNOPSIS
    #include <sys/ddi_intr.h>

    int ddi_intr_set_nreq(dev_info_t *dip, int nreq);

INTERFACE LEVEL
    Solaris DDI specific (Solaris DDI).

PARAMETERS
    dip		Pointer to the dev_info structure

    nreq	Number of interrupts requested.

DESCRIPTION
    The ddi_intr_set_nreq() function changes the number of interrupts
    requested by a device driver.

    The nreq parameter is initially set to be equal to the count
    parameter when the device driver first calls the ddi_intr_alloc(9F)
    function.  If the device driver detects changes in its workload,
    and it decides it needs more or less interrupt vectors, then it
    may use the ddi_intr_set_nreq() function to adjust its nreq
    parameter at arbitrary times.

    The nreq parameter can be any value between 1 and the maximum
    number of interrupts supported by the device hardware, as reported
    by a call to the ddi_intr_get_nintrs(9F) function.  The driver will
    receive a callback notifying it in cases when it must release any
    previously allocated interrupts, or when it is allowed to allocate
    more interrupts as a result of its new nreq parameter.

    The ddi_intr_set_nreq() function is not supported unless a driver
    is already consuming interrupts, and if it has a registered callback
    handler that can process actions related to changes in interrupt
    availability.  See ddi_cb_register(9F) for an explanation on how
    to enable this functionality.

RETURN VALUES
    The ddi_intr_set_nreq() function returns:

    DDI_SUCCESS		On success.

    DDI_EINVAL		The operation is invalid because the nreq
			parameter is not a legal value.

    DDI_ENOTSUP		The operation is not supported.  The driver
			must have a registered callback, and the
			system must have interrupt pools implemented.

    DDI_FAILURE		On any implementation specific failure.

ATTRIBUTES
    See attributes(5) for descriptions of the following attributes:

     ____________________________________________________________
    |      ATTRIBUTE TYPE	|	    ATTRIBUTE VALUE      |
    |___________________________|________________________________|
    | Interface Stability	| Committed                      |
    |___________________________|________________________________|
    | MT-Level			| MT-Safe                        |
    |___________________________|________________________________|

SEE ALSO
    attributes(5),		ddi_intr_alloc(9F),
    ddi_intr_get_nintrs(9F),	ddi_cb_register(9F)