'\" te
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.TH PCI_REPORT_PMCAP 9F "Aug 13, 1999"
.SH NAME
pci_report_pmcap \- Report Power Management capability of a PCI device
.SH SYNOPSIS
.nf
#include <sys/ddi.h>
#include <sys/sunddi.h>



\fBint\fR \fBpci_report_pmcap\fR(\fBdev_info_t *\fR\fIdip\fR,  int \fIcap,\fR void *\fIarg\fR);
.fi

.SH INTERFACE LEVEL
illumos DDI specific (illumos DDI)
.SH PARAMETERS
.ne 2
.na
\fB\fIdip\fR\fR
.ad
.RS 7n
Pointer to the device's \fBdev_info\fR structure
.RE

.sp
.ne 2
.na
\fB\fIcap\fR\fR
.ad
.RS 7n
Power management capability
.RE

.sp
.ne 2
.na
\fB\fIarg\fR\fR
.ad
.RS 7n
Argument for the capability
.RE

.SH DESCRIPTION
Some PCI devices provide power management capabilities in addition to those
provided by the PCI Power Management Specification. The
\fBpci_report_pmcap()\fR function reports those Power Management capabilities
of the PCI device to the framework. Framework supports dynamic changing of the
capability by allowing \fBpci_report_pmcap()\fR to be called multiple times.
Following are the supported capabilities as indicated by the \fBcap\fR:
.sp
.LP
\fBPCI_PM_IDLESPEED\fR \(em The \fBPCI_PM_IDLESPEED\fR value indicates the
lowest PCI clock speed that a device can tolerate when idle, and is  applicable
only to 33 MHz PCI bus. \fBarg\fR represents the lowest possible idle speed in
KHz (1 KHz is 1000 Hz). The integer value representing the speed should be cast
to \fB(void *)\fRbefore passing as \fBarg\fR to \fBpci_report_pmcap()\fR.
.sp
.LP
The special values of \fBarg\fR are:
.sp
.ne 2
.na
\fB\fBPCI_PM_IDLESPEED_ANY\fR\fR
.ad
.RS 25n
The device can tolerate any idle clock speed.
.RE

.sp
.ne 2
.na
\fB\fBPCI_PM_IDLESPEED_NONE\fR\fR
.ad
.RS 25n
The device cannot tolerate slowing down of PCI clock even when idle.
.RE

.sp
.LP
If the driver doesn't make this call, \fBPCI_PM_IDLESPEED_NONE\fR is assumed.
In this case, one offending device can keep the entire bus from being power
managed.
.SH RETURN VALUES
The \fBpci_report_pmcap()\fR function returns:
.sp
.ne 2
.na
\fB\fBDDI_SUCCESS\fR\fR
.ad
.RS 15n
Successful reporting of the capability
.RE

.sp
.ne 2
.na
\fB\fBDDI_FAILURE\fR\fR
.ad
.RS 15n
Failure to report capability because of invalid argument(s)
.RE

.SH CONTEXT
The \fBpci_report_pmcap()\fR function can be called from user, kernel and
interrupt context.
.SH EXAMPLES
1. A device driver knows that the device it controls works with any clock
between DC and 33 MHz as specified in \fISection 4.2.3.1: Clock Specification
\fR of the \fIPCI Bus Specification Revision 2.1\fR. The device driver makes
the following call from its \fBattach\fR(9E):
.sp
.in +2
.nf
if (pci_report_pmcap(dip, PCI_PM_IDLESPEED, PCI_PM_IDLESPEED_ANY) !=
            DDI_SUCCESS)
                cmn_err(CE_WARN, "%s%d: pci_report_pmcap failed\fB\en\fR",
                    ddi_driver_name(dip), ddi_get_instance(dip));
.fi
.in -2

.sp
.LP
2. A device driver controls a 10/100 Mb Ethernet device which runs the device
state machine on the chip from the PCI clock. For the device state machine to
receive packets at 100 Mb, the PCI clock cannot drop below 4 MHz. The driver
makes the following call whenever it negotiates a 100 Mb Ethernet connection:
.sp
.in +2
.nf
if (pci_report_pmcap(dip,  PCI_PM_IDLESPEED, (void *)4000) !=
               DDI_SUCCESS)
                cmn_err(CE_WARN, "%s%d: pci_report_pmcap failed\fB\en\fR",
                    ddi_driver_name(dip), ddi_get_instance(dip));
.fi
.in -2

.SH ATTRIBUTES
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

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

.SH SEE ALSO
\fIWriting Device Drivers\fR
.sp
.LP
\fIPCI Bus Power Management Interface Specification Version 1.1\fR
.sp
.LP
\fIPCI Bus Specification Revision 2.1\fR