svn commit: r232363 - head/share/man/man9
John Baldwin
jhb at FreeBSD.org
Thu Mar 1 20:36:50 UTC 2012
Author: jhb
Date: Thu Mar 1 20:36:50 2012
New Revision: 232363
URL: http://svn.freebsd.org/changeset/base/232363
Log:
Update the documentation on pci_get/set_powerstate(). These methods are
not ACPI-specific at all, but deal with PCI power states. Also,
pci_set_powerstate() fails with EOPNOTSUPP if a request is made that the
underlying device does not support rather than falling back to somehow
setting D0.
Modified:
head/share/man/man9/pci.9
Modified: head/share/man/man9/pci.9
==============================================================================
--- head/share/man/man9/pci.9 Thu Mar 1 20:32:02 2012 (r232362)
+++ head/share/man/man9/pci.9 Thu Mar 1 20:36:50 2012 (r232363)
@@ -145,13 +145,13 @@ the configuration space.
.Pp
The
.Fn pci_get_powerstate
-function returns the current ACPI power state of the device
+function returns the current power state of the device
.Fa dev .
If the device does not support power management capabilities, then the default
state of
.Dv PCI_POWERSTATE_D0
is returned.
-The following power states are defined by ACPI:
+The following power states are defined by PCI:
.Bl -hang -width ".Dv PCI_POWERSTATE_UNKNOWN"
.It Dv PCI_POWERSTATE_D0
State in which device is on and running.
@@ -183,15 +183,13 @@ The
.Fn pci_set_powerstate
function is used to transition the device
.Fa dev
-to the ACPI power state
+to the PCI power state
.Fa state .
-It checks to see if the device is PCI 2.2 compliant.
-If so, it checks the
-capabilities pointer to determine which power states the device supports.
-If the device does not have power management capabilities, the default state
-of
-.Dv PCI_POWERSTATE_D0
-is set.
+If the device does not support power management capabilities or
+it does not support the specific power state
+.Fa state ,
+then the function will fail with
+.Er EOPNOTSUPP .
.Pp
The
.Fn pci_save_state
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