DDI_INTR_HILEVEL(9F) Kernel Functions for Drivers DDI_INTR_HILEVEL(9F)

NAME

ddi_intr_hilevel - indicate interrupt handler type

SYNOPSIS

#include <sys/ddi.h>
#include <sys/sunddi.h>


int ddi_intr_hilevel(dev_info_t *dip, uint_t inumber);

INTERFACE LEVEL

illumos DDI specific (illumos DDI). This interface is obsolete. Use the
new interrupt interfaces referenced in Intro(9F). Refer to Writing Device
Drivers for more information.

PARAMETERS

dip
Pointer to dev_info structure.


inumber
Interrupt number.

DESCRIPTION

The ddi_intr_hilevel() function returns non-zero if the specified
interrupt is a "high level" interrupt.


High level interrupts must be handled without using system services that
manipulate thread or process states, because these interrupts are not
blocked by the scheduler.


In addition, high level interrupt handlers must take care to do a minimum
of work because they are not preemptable.


A typical high level interrupt handler would put data into a circular
buffer and schedule a soft interrupt by calling ddi_trigger_softintr().
The circular buffer could be protected by using a mutex that was properly
initialized for the interrupt handler.


The ddi_intr_hilevel() function can be used before calling ddi_add_intr()
to decide which type of interrupt handler should be used. Most device
drivers are designed with the knowledge that the devices they support
will always generate low level interrupts, however some devices, for
example those using SBus or VME bus level 6 or 7 interrupts must use this
test because on some machines those interrupts are high level (above the
scheduler level) and on other machines they are not.

RETURN VALUES

non-zero
indicates a high-level interrupt.

CONTEXT

These functions can be called from useruser, interrupt, or kernel
context.

ATTRIBUTES

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


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Obsolete |
+--------------------+-----------------+

SEE ALSO

Intro(9F), ddi_add_intr(9F), mutex(9F)


Writing Device Drivers


January 16, 2006 DDI_INTR_HILEVEL(9F)