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

ddi_intr_hilevel - indicate interrupt handler type

#include <sys/ddi.h>
#include <sys/sunddi.h>
int ddi_intr_hilevel(dev_info_t *dip, uint_t inumber);

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 This interface is obsolete.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.

dip
Pointer to dev_info structure.

inumber

Interrupt number.

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.

non-zero
indicates a high-level interrupt.

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

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

ATTRIBUTE TYPE ATTRIBUTE VALUE
Interface Stability Obsolete

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

Writing Device Drivers

January 16, 2006 OmniOS