On Fri, Dec 15, 2017 at 03:07:18AM +0100, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > It is incorrect to call pci_restore_state() for devices in low-power > states (D1-D3), as that involves the restoration of MSI setup which > requires MMIO to be operational and that is only the case in D0. > > However, pci_pm_thaw_noirq() may do that if the driver's "freeze" > callbacks put the device into a low-power state, so fix it by making > it force devices into D0 via pci_set_power_state() instead of trying > to "update" their power state which is pointless. > > Fixes: e60514bd4485 (PCI/PM: Restore the status of PCI devices across hibernation) > Cc: 4.13+ <stable@xxxxxxxxxxxxxxx> # 4.13+ > Reported-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Reported-by: Maarten Lankhorst <dev@xxxxxxxxxxxxxx> > Tested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Tested-by: Maarten Lankhorst <dev@xxxxxxxxxxxxxx> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> Let me know if you want me to take this. I don't have anything currently queued up that touches pci-driver.c, so I'm happy if you take it yourself. > --- > > The bug is not as old as I thought, actually. > > Yes, we did the pci_update_current_state() in pci_pm_thaw_noirq() > forever, but it started to be problematic in 4.13, when we started > to call pci_restore_state() in addition to it to fix another issue. > > --- > drivers/pci/pci-driver.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > Index: linux-pm/drivers/pci/pci-driver.c > =================================================================== > --- linux-pm.orig/drivers/pci/pci-driver.c > +++ linux-pm/drivers/pci/pci-driver.c > @@ -1027,7 +1027,12 @@ static int pci_pm_thaw_noirq(struct devi > if (pci_has_legacy_pm_support(pci_dev)) > return pci_legacy_resume_early(dev); > > - pci_update_current_state(pci_dev, PCI_D0); > + /* > + * pci_restore_state() requires the device to be in D0 (because of MSI > + * restoration among other things), so force it into D0 in case the > + * driver's "freeze" callbacks put it into a low-power state directly. > + */ > + pci_set_power_state(pci_dev, PCI_D0); > pci_restore_state(pci_dev); > > if (drv && drv->pm && drv->pm->thaw_noirq) >
