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| author | Lukas Wunner <lukas@wunner.de> | 2016-09-18 05:39:20 +0200 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2016-09-28 11:46:51 -0500 |
| commit | cc7cc02bada84f0d707aa5b6d2ef8728a2e1f911 (patch) | |
| tree | f1d963b141e5d6fae283afa49e4841faeeedb6e8 /drivers/pci/pci-acpi.c | |
| parent | 4132a577a0a7e75b938d2ae49c7a16b358f60661 (diff) | |
| download | linux-cc7cc02bada84f0d707aa5b6d2ef8728a2e1f911.tar.gz linux-cc7cc02bada84f0d707aa5b6d2ef8728a2e1f911.tar.bz2 linux-cc7cc02bada84f0d707aa5b6d2ef8728a2e1f911.zip | |
PCI: Query platform firmware for device power state
Usually the most accurate way to determine a PCI device's power state is to
read its PM Control & Status Register. There are two cases however when
this is not an option: If the device doesn't have the PM capability at
all, or if it is in D3cold (in which case its config space is
inaccessible).
In both cases, we can alternatively query the platform firmware for its
opinion on the device's power state. To facilitate this, augment struct
pci_platform_pm_ops with a ->get_power callback and implement it for
acpi_pci_platform_pm (the only pci_platform_pm_ops existing so far).
It is used by a forthcoming commit to let pci_update_current_state()
recognize D3cold.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/pci/pci-acpi.c')
| -rw-r--r-- | drivers/pci/pci-acpi.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c index 9a033e8ee9a4..d966d47c9e80 100644 --- a/drivers/pci/pci-acpi.c +++ b/drivers/pci/pci-acpi.c @@ -452,6 +452,27 @@ static int acpi_pci_set_power_state(struct pci_dev *dev, pci_power_t state) return error; } +static pci_power_t acpi_pci_get_power_state(struct pci_dev *dev) +{ + struct acpi_device *adev = ACPI_COMPANION(&dev->dev); + static const pci_power_t state_conv[] = { + [ACPI_STATE_D0] = PCI_D0, + [ACPI_STATE_D1] = PCI_D1, + [ACPI_STATE_D2] = PCI_D2, + [ACPI_STATE_D3_HOT] = PCI_D3hot, + [ACPI_STATE_D3_COLD] = PCI_D3cold, + }; + int state; + + if (!adev || !acpi_device_power_manageable(adev)) + return PCI_UNKNOWN; + + if (acpi_device_get_power(adev, &state) || state == ACPI_STATE_UNKNOWN) + return PCI_UNKNOWN; + + return state_conv[state]; +} + static bool acpi_pci_can_wakeup(struct pci_dev *dev) { struct acpi_device *adev = ACPI_COMPANION(&dev->dev); @@ -534,6 +555,7 @@ static bool acpi_pci_need_resume(struct pci_dev *dev) static const struct pci_platform_pm_ops acpi_pci_platform_pm = { .is_manageable = acpi_pci_power_manageable, .set_state = acpi_pci_set_power_state, + .get_state = acpi_pci_get_power_state, .choose_state = acpi_pci_choose_state, .sleep_wake = acpi_pci_sleep_wake, .run_wake = acpi_pci_run_wake, |