pci_report_pmcap(9F) Kernel Functions for Drivers pci_report_pmcap(9F)NAMEpci_report_pmcap - Report Power Management capability of a PCI device
SYNOPSIS
#include <sys/ddi.h>
#include <sys/sunddi.h>
int pci_report_pmcap(dev_info_t *dip, int cap, void *arg);
INTERFACE LEVEL
Solaris DDI specific (Solaris DDI)
PARAMETERS
dip Pointer to the device's dev_info structure
cap Power management capability
arg Argument for the capability
DESCRIPTION
Some PCI devices provide power management capabilities in addition to
those provided by the PCI Power Management Specification. The
pci_report_pmcap(9F) function reports those Power Management capabili‐
ties of the PCI device to the framework. Framework supports dynamic
changing of the capability by allowing pci_report_pmcap(9F) to be
called multiple times. Following are the supported capabilities as
indicated by the cap:
PCI_PM_IDLESPEED — The PCI_PM_IDLESPEED value indicates the lowest PCI
clock speed that a device can tolerate when idle, and is applicable
only to 33 MHz PCI bus. arg represents the lowest possible idle speed
in KHz (1 KHz is 1000 Hz). The integer value representing the speed
should be cast to (void *) before passing as arg to
pci_report_pmcap(9F).
The special values of arg are:
PCI_PM_IDLESPEED_ANY The device can tolerate any idle clock speed.
PCI_PM_IDLESPEED_NONE The device cannot tolerate slowing down of PCI
clock even when idle.
If the driver doesn't make this call, PCI_PM_IDLESPEED_NONE is assumed.
In this case, one offending device can keep the entire bus from being
power managed.
RETURN VALUES
The pci_report_pmcap(9F) function returns:
DDI_SUCCESS Successful reporting of the capability
DDI_FAILURE Failure to report capability because of invalid argu‐
ment(s)CONTEXT
The pci_report_pmcap(9F) function can be called from user, kernel and
interrupt context.
EXAMPLES
1. A device driver knows that the device it controls works with any
clock between DC and 33 MHz as specified in Section 4.2.3.1: Clock
Specification of the PCI Bus Specification Revision 2.1. The device
driver makes the following call from its attach(9E):
if (pci_report_pmcap(dip, PCI_PM_IDLESPEED, PCI_PM_IDLESPEED_ANY) !=
DDI_SUCCESS)
cmn_err(CE_WARN, "%s%d: pci_report_pmcap failed\n",
ddi_driver_name(dip), ddi_get_instance(dip));
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:
if (pci_report_pmcap(dip, PCI_PM_IDLESPEED, (void *)4000) !=
DDI_SUCCESS)
cmn_err(CE_WARN, "%s%d: pci_report_pmcap failed\n",
ddi_driver_name(dip), ddi_get_instance(dip));
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌──────────────────────────┬────────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├──────────────────────────┼────────────────────────────────┤
│Interface Stability │ Evolving │
└──────────────────────────┴────────────────────────────────┘
SEE ALSO
Writing Device Drivers
PCI Bus Power Management Interface Specification Version 1.1
PCI Bus Specification Revision 2.1
SunOS 5.10 13 August 1999 pci_report_pmcap(9F)
