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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 11:49:21 -0500 |
| commit | a0d2a959d3da343554523d26902de1d40a9e5c28 (patch) | |
| tree | 9fe0d30920a8e2a3107d67a451ab48d1bf394502 | |
| parent | a6a64026c0cd1a76a0c8ab1c05a421aa4821887b (diff) | |
| download | linux-a0d2a959d3da343554523d26902de1d40a9e5c28.tar.bz2 | |
PCI: Avoid unnecessary resume after direct-complete
Commit 58a1fbbb2ee8 ("PM / PCI / ACPI: Kick devices that might have been
reset by firmware") added a runtime resume for devices that were runtime
suspended when the system entered sleep.
The motivation was that devices might be in a reset-power-on state after
waking from system sleep, so their power state as perceived by Linux
(stored in pci_dev->current_state) would no longer reflect reality. By
resuming such devices, we allow them to return to a low-power state via
autosuspend and also bring their current_state in sync with reality.
However for devices that are *not* in a reset-power-on state, doing an
unconditional resume wastes energy. A more refined approach is called for
which issues a runtime resume only if the power state after direct-complete
is shallower than it was before. To achieve this, update the device's
current_state and compare it to its pre-sleep value.
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>
| -rw-r--r-- | drivers/pci/pci-driver.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index e39a67c8ef39..fd4b9c48fd2a 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -684,8 +684,19 @@ static int pci_pm_prepare(struct device *dev) static void pci_pm_complete(struct device *dev) { - pci_dev_complete_resume(to_pci_dev(dev)); - pm_complete_with_resume_check(dev); + struct pci_dev *pci_dev = to_pci_dev(dev); + + pci_dev_complete_resume(pci_dev); + pm_generic_complete(dev); + + /* Resume device if platform firmware has put it in reset-power-on */ + if (dev->power.direct_complete && pm_resume_via_firmware()) { + pci_power_t pre_sleep_state = pci_dev->current_state; + + pci_update_current_state(pci_dev, pci_dev->current_state); + if (pci_dev->current_state < pre_sleep_state) + pm_request_resume(dev); + } } #else /* !CONFIG_PM_SLEEP */ |