'\" te
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.TH DDI_INTR_HILEVEL 9F "Jan 16, 2006"
.SH NAME
ddi_intr_hilevel \- indicate interrupt handler type
.SH SYNOPSIS
.nf
#include <sys/ddi.h>
#include <sys/sunddi.h>



\fBint\fR \fBddi_intr_hilevel\fR(\fBdev_info_t *\fR\fIdip\fR, \fBuint_t\fR \fIinumber\fR);
.fi

.SH INTERFACE LEVEL
illumos DDI specific (illumos DDI). This interface is obsolete. Use the new
interrupt interfaces referenced in \fBIntro\fR(9F). Refer to \fIWriting Device
Drivers\fR for more information.
.SH PARAMETERS
.ne 2
.na
\fB\fIdip\fR\fR
.ad
.RS 11n
Pointer to \fBdev_info\fR structure.
.RE

.sp
.ne 2
.na
\fB\fIinumber\fR\fR
.ad
.RS 11n
Interrupt number.
.RE

.SH DESCRIPTION
The \fBddi_intr_hilevel()\fR function returns non-zero if the specified
interrupt is a "high level" interrupt.
.sp
.LP
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.
.sp
.LP
In addition, high level interrupt handlers must take care to do a minimum of
work because they are not preemptable.
.sp
.LP
A typical high level interrupt handler would put data into a circular buffer
and schedule a soft interrupt by calling \fBddi_trigger_softintr()\fR. The
circular buffer could be protected by using a mutex that was properly
initialized for the interrupt handler.
.sp
.LP
The \fBddi_intr_hilevel()\fR function can be used before calling
\fBddi_add_intr()\fR 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.
.SH RETURN VALUES
.ne 2
.na
\fBnon-zero\fR
.ad
.RS 12n
indicates a high-level interrupt.
.RE

.SH CONTEXT
These functions can be called from useruser, interrupt, or kernel context.
.SH ATTRIBUTES
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Obsolete
.TE

.SH SEE ALSO
.BR Intro (9F),
.BR ddi_add_intr (9F),
.BR mutex (9F)
.sp
.LP
\fIWriting Device Drivers\fR