• Rafael J. Wysocki's avatar
    PCI / PM: Take SMART_SUSPEND driver flag into account · c4b65157
    Rafael J. Wysocki authored
    Make the PCI bus type take DPM_FLAG_SMART_SUSPEND into account in its
    system-wide PM callbacks and make sure that all code that should not
    run in parallel with pci_pm_runtime_resume() is executed in the "late"
    phases of system suspend, freeze and poweroff transitions.
    
    [Note that the pm_runtime_suspended() check in pci_dev_keep_suspended()
    is an optimization, because if is not passed, all of the subsequent
    checks may be skipped and some of them are much more overhead in
    general.]
    
    Also use the observation that if the device is in runtime suspend
    at the beginning of the "late" phase of a system-wide suspend-like
    transition, its state cannot change going forward (runtime PM is
    disabled for it at that time) until the transition is over and the
    subsequent system-wide PM callbacks should be skipped for it (as
    they generally assume the device to not be suspended), so add checks
    for that in pci_pm_suspend_late/noirq(), pci_pm_freeze_late/noirq()
    and pci_pm_poweroff_late/noirq().
    
    Moreover, if pci_pm_resume_noirq() or pci_pm_restore_noirq() is
    called during the subsequent system-wide resume transition and if
    the device was left in runtime suspend previously, its runtime PM
    status needs to be changed to "active" as it is going to be put
    into the full-power state, so add checks for that too to these
    functions.
    
    In turn, if pci_pm_thaw_noirq() runs after the device has been
    left in runtime suspend, the subsequent "thaw" callbacks need
    to be skipped for it (as they may not work correctly with a
    suspended device), so set the power.direct_complete flag for the
    device then to make the PM core skip those callbacks.
    
    In addition to the above add a core helper for checking if
    DPM_FLAG_SMART_SUSPEND is set and the device runtime PM status is
    "suspended" at the same time, which is done quite often in the new
    code (and will be done elsewhere going forward too).
    Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
    Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    Acked-by: default avatarBjorn Helgaas <bhelgaas@google.com>
    c4b65157
pci.txt 55.6 KB