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.limonciello@xxxxxxxx> > --- > 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. > } > - /* > - * 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; >
