On Mon, Jun 12, 2017 at 10:49:40PM +0200, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > hcd_pci_resume_noirq() used as a universal _resume_noirq handler for > PCI USB controllers calls pci_back_from_sleep() which is unnecessary > and may become problematic. > > It is unnecessary, because the PCI bus type carries out post-suspend > cleanup of all PCI devices during resume and that covers all things > done by the pci_back_from_sleep(). There is no reason why USB cannot > follow all of the other PCI devices in that respect. > > It will become problematic after subsequent changes that make it > possible to go back to sleep again after executing dpm_resume_noirq() > if no valid system wakeup events have been detected at that point. > Namely, calling pci_back_from_sleep() at the _resume_noirq stage > will cause the wakeup status of the devices in question to be cleared > and if any of them has triggered system wakeup, that event may be > missed then. > > For the above reasons, drop the pci_back_from_sleep() invocation > from hcd_pci_resume_noirq(). > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
