On Wednesday, September 18, 2019 11:31:19 PM CEST Rafael J. Wysocki wrote: > On Thursday, September 12, 2019 1:42:33 AM CEST Mario Limonciello wrote: > > The action of saving the PCI state will cause numerous PCI configuration > > space reads which depending upon the vendor implementation may cause > > the drive to exit the deepest NVMe state. > > > > In these cases ASPM will typically resolve the PCIe link state and APST > > may resolve the NVMe power state. However it has also been observed > > that this register access after quiesced will cause PC10 failure > > on some device combinations. > > > > To resolve this, move the PCI state saving to before SetFeatures has been > > called. This has been proven to resolve the issue across a 5000 sample > > test on previously failing disk/system combinations. > > This sounds reasonable to me, but it would be nice to CC that to linux-pm > and/or linux-pci too. > > > Signed-off-by: Mario Limonciello <mario.limoncie...@dell.com> > > --- > > drivers/nvme/host/pci.c | 13 +++++++------ > > 1 file changed, 7 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c > > index 732d5b6..9b3fed4 100644 > > --- a/drivers/nvme/host/pci.c > > +++ b/drivers/nvme/host/pci.c > > @@ -2894,6 +2894,13 @@ static int nvme_suspend(struct device *dev) > > if (ret < 0) > > goto unfreeze; > > > > + /* > > + * A saved state prevents pci pm from generically controlling the > > + * device's power. If we're using protocol specific settings, we don't > > + * want pci interfering. > > + */ > > + pci_save_state(pdev); > > + > > ret = nvme_set_power_state(ctrl, ctrl->npss); > > if (ret < 0) > > goto unfreeze; > > @@ -2908,12 +2915,6 @@ static int nvme_suspend(struct device *dev) > > This is the case in which the PCI layer is expected to put the device into > D3, so you need > > pdev->state_saved = 0; > > at this point, because you have saved the config space already. > > > ret = 0; > > goto unfreeze; > > And here you don't need to jump to "unfreeze" any more.
BTW, doing nvme_dev_disable() before nvme_unfreeze() looks odd to me. Maybe it would be better to do "unfreeze" and then "disable" in this case? > > > } > > - /* > > - * A saved state prevents pci pm from generically controlling the > > - * device's power. If we're using protocol specific settings, we don't > > - * want pci interfering. > > - */ > > - pci_save_state(pdev); > > unfreeze: > > nvme_unfreeze(ctrl); > > return ret; > > > > > > >
