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PCI / PM: Support for LEAVE_SUSPENDED driver flag 

Add support for DPM_FLAG_LEAVE_SUSPENDED to the PCI bus type by
making it (a) set the power.may_skip_resume status bit for devices
that, from its perspective, may be left in suspend after system
wakeup from sleep and (b) return early from pci_pm_resume_noirq()
for devices whose remaining resume callbacks during the transition
under way are going to be skipped by the PM core.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
hifive-unleashed-5.1
Rafael J. Wysocki 2017-11-18 15:33:52 +01:00
parent 0d4b54c6fe
commit bd755d770a
2 changed files with 28 additions and 2 deletions
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11
Documentation/power/pci.txt
View File

@ -994,6 +994,17 @@ into D0 going forward), but if it is in runtime suspend in pci_pm_thaw_noirq(),
the function will set the power.direct_complete flag for it (to make the PM core
skip the subsequent "thaw" callbacks for it) and return.
Setting the DPM_FLAG_LEAVE_SUSPENDED flag means that the driver prefers the
device to be left in suspend after system-wide transitions to the working state.
This flag is checked by the PM core, but the PCI bus type informs the PM core
which devices may be left in suspend from its perspective (that happens during
the "noirq" phase of system-wide suspend and analogous transitions) and next it
uses the dev_pm_may_skip_resume() helper to decide whether or not to return from
pci_pm_resume_noirq() early, as the PM core will skip the remaining resume
callbacks for the device during the transition under way and will set its
runtime PM status to "suspended" if dev_pm_may_skip_resume() returns "true" for
it.
3.2. Device Runtime Power Management
------------------------------------
In addition to providing device power management callbacks PCI device drivers

19
drivers/pci/pci-driver.c
View File

@ -699,7 +699,7 @@ static void pci_pm_complete(struct device *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()) {
if (pm_runtime_suspended(dev) && pm_resume_via_firmware()) {
pci_power_t pre_sleep_state = pci_dev->current_state;
pci_update_current_state(pci_dev, pci_dev->current_state);
@ -783,8 +783,10 @@ static int pci_pm_suspend_noirq(struct device *dev)
struct pci_dev *pci_dev = to_pci_dev(dev);
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
if (dev_pm_smart_suspend_and_suspended(dev))
if (dev_pm_smart_suspend_and_suspended(dev)) {
dev->power.may_skip_resume = true;
return 0;
}
if (pci_has_legacy_pm_support(pci_dev))
return pci_legacy_suspend_late(dev, PMSG_SUSPEND);
@ -838,6 +840,16 @@ static int pci_pm_suspend_noirq(struct device *dev)
Fixup:
pci_fixup_device(pci_fixup_suspend_late, pci_dev);
/*
* If the target system sleep state is suspend-to-idle, it is sufficient
* to check whether or not the device's wakeup settings are good for
* runtime PM. Otherwise, the pm_resume_via_firmware() check will cause
* pci_pm_complete() to take care of fixing up the device's state
* anyway, if need be.
*/
dev->power.may_skip_resume = device_may_wakeup(dev) ||
!device_can_wakeup(dev);
return 0;
}
@ -847,6 +859,9 @@ static int pci_pm_resume_noirq(struct device *dev)
struct device_driver *drv = dev->driver;
int error = 0;
if (dev_pm_may_skip_resume(dev))
return 0;
/*
* Devices with DPM_FLAG_SMART_SUSPEND may be left in runtime suspend
* during system suspend, so update their runtime PM status to "active"