On Tuesday, October 15, 2019 1:00:10 AM CEST Bjorn Helgaas wrote: > From: Dexuan Cui <de...@microsoft.com> > > pci_pm_thaw_noirq() is supposed to return the device to D0 and restore its > configuration registers, but previously it only did that for devices whose > drivers implemented the new power management ops. > > Hibernation, e.g., via "echo disk > /sys/power/state", involves freezing > devices, creating a hibernation image, thawing devices, writing the image, > and powering off. The fact that thawing did not return devices with legacy > power management to D0 caused errors, e.g., in this path: > > pci_pm_thaw_noirq > if (pci_has_legacy_pm_support(pci_dev)) # true for Mellanox VF driver > return pci_legacy_resume_early(dev) # ... legacy PM skips the rest > pci_set_power_state(pci_dev, PCI_D0) > pci_restore_state(pci_dev) > pci_pm_thaw > if (pci_has_legacy_pm_support(pci_dev)) > pci_legacy_resume > drv->resume > mlx4_resume > ... > pci_enable_msix_range > ... > if (dev->current_state != PCI_D0) # <--- > return -EINVAL; > > which caused these warnings: > > mlx4_core a6d1:00:02.0: INTx is not supported in multi-function mode, > aborting > PM: dpm_run_callback(): pci_pm_thaw+0x0/0xd7 returns -95 > PM: Device a6d1:00:02.0 failed to thaw: error -95 > > Return devices to D0 and restore config registers for all devices, not just > those whose drivers support new power management. > > [bhelgaas: also call pci_restore_state() before pci_legacy_resume_early(), > update comment, add stable tag, commit log] > Link: > https://lore.kernel.org/r/ku1p153mb016637caead346f0aa8e3801bf...@ku1p153mb0166.apcp153.prod.outlook.com > Signed-off-by: Dexuan Cui <de...@microsoft.com> > Signed-off-by: Bjorn Helgaas <bhelg...@google.com> > Cc: sta...@vger.kernel.org # v4.13+
No issues found, so Reviewed-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > --- > drivers/pci/pci-driver.c | 17 +++++++++++------ > 1 file changed, 11 insertions(+), 6 deletions(-) > > diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c > index a8124e47bf6e..d4ac8ce8c1f9 100644 > --- a/drivers/pci/pci-driver.c > +++ b/drivers/pci/pci-driver.c > @@ -1076,17 +1076,22 @@ static int pci_pm_thaw_noirq(struct device *dev) > return error; > } > > - if (pci_has_legacy_pm_support(pci_dev)) > - return pci_legacy_resume_early(dev); > - > /* > - * 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. > + * Both the legacy ->resume_early() and the new pm->thaw_noirq() > + * callbacks assume the device has been returned to D0 and its > + * config state has been restored. > + * > + * In addition, pci_restore_state() restores MSI-X state in MMIO > + * space, which requires the device to be in D0, so return it to D0 > + * in case the driver's "freeze" callbacks put it into a low-power > + * state. > */ > pci_set_power_state(pci_dev, PCI_D0); > pci_restore_state(pci_dev); > > + if (pci_has_legacy_pm_support(pci_dev)) > + return pci_legacy_resume_early(dev); > + > if (drv && drv->pm && drv->pm->thaw_noirq) > error = drv->pm->thaw_noirq(dev); > >
