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author | jhb <jhb@FreeBSD.org> | 2012-03-01 20:36:50 +0000 |
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committer | jhb <jhb@FreeBSD.org> | 2012-03-01 20:36:50 +0000 |
commit | 20f70f7f55cbd6a05571983524a210f9ea3b7066 (patch) | |
tree | caaac6451496eb3be3b4fa972802a24d4dabe933 /share/man/man9/pci.9 | |
parent | e03043889a2018be37c98fc3a9d57843a4ab819a (diff) | |
download | FreeBSD-src-20f70f7f55cbd6a05571983524a210f9ea3b7066.zip FreeBSD-src-20f70f7f55cbd6a05571983524a210f9ea3b7066.tar.gz |
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.
Diffstat (limited to 'share/man/man9/pci.9')
-rw-r--r-- | share/man/man9/pci.9 | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/share/man/man9/pci.9 b/share/man/man9/pci.9 index 16cca62..37a4f9a 100644 --- a/share/man/man9/pci.9 +++ b/share/man/man9/pci.9 @@ -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 |