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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-04-18 19:52:08 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-04-24 22:31:14 +0300
commit6e176bf8d46194353163c2cb660808bc633b45d9 (patch)
tree8f3ea97fce71a053ec261d31a19aeb1d0c43df28 /Documentation/power/pci.rst
parent30205377ddbb717ee451e872fd59511f4f76373d (diff)
downloadlinux-6e176bf8d46194353163c2cb660808bc633b45d9.tar.xz
PM: sleep: core: Do not skip callbacks in the resume phase
The current code in device_resume_noirq() causes the entire early resume and resume phases of device suspend to be skipped for devices for which the noirq resume phase have been skipped (due to the LEAVE_SUSPENDED flag being set) on the premise that those devices should stay in runtime-suspend after system-wide resume. However, that may not be correct in two situations. First, the middle layer (subsystem) noirq resume callback may be missing for a given device, but its early resume callback may be present and it may need to do something even if it decides to skip the driver callback. Second, if the device's wakeup settings were adjusted in the suspend phase without resuming the device (that was in runtime suspend at that time), they most likely need to be adjusted again in the resume phase and so the driver callback in that phase needs to be run. For the above reason, modify the core to allow the middle layer ->resume_late callback to run even if its ->resume_noirq callback is missing (and the core has skipped the driver-level callback in that phase) and to allow all device callbacks to run in the resume phase. Also make the core set the PM-runtime status of devices with SMART_SUSPEND set whose resume callbacks are not skipped to "active" in the "noirq" resume phase and update the affected subsystems (PCI and ACPI) accordingly. After this change, middle-layer (subsystem) callbacks will always be invoked in all phases of system suspend and resume and driver callbacks will always run in the prepare, suspend, resume, and complete phases for all devices. For devices with SMART_SUSPEND set, driver callbacks will be skipped in the late and noirq phases of system suspend if those devices remain in runtime suspend in __device_suspend_late(). Driver callbacks will also be skipped for them during the noirq and early phases of the "thaw" transition related to hibernation in that case. Setting LEAVE_SUSPENDED means that the driver allows its callbacks to be skipped in the noirq and early phases of system resume, but some additional conditions need to be met for that to happen (among other things, the power.may_skip_resume flag needs to be set for the device during system suspend for the driver callbacks to be skipped during the subsequent resume transition). For all devices with SMART_SUSPEND set whose driver callbacks are invoked during system resume, the PM-runtime status will be set to "active" (by the core). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'Documentation/power/pci.rst')
-rw-r--r--Documentation/power/pci.rst5
1 files changed, 1 insertions, 4 deletions
diff --git a/Documentation/power/pci.rst b/Documentation/power/pci.rst
index 0924d29636ad..a39b2461919a 100644
--- a/Documentation/power/pci.rst
+++ b/Documentation/power/pci.rst
@@ -1035,10 +1035,7 @@ 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.
+pci_pm_resume_noirq() and pci_pm_resume_early() upfront.
3.2. Device Runtime Power Management
------------------------------------