Hi Bjorn, I have verified this patch, it works fine for me. Thanks & Regards, Srinath. On Fri, Apr 20, 2018 at 2:35 AM, Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > > When in the ASPM L1.0 state (but not the PCI-PM L1.0 state), the most > recent LTR value and the LTR_L1.2_THRESHOLD determines whether the link > enters the L1.2 substate. > > If we don't have LTR enabled, prevent the use of ASPM L1.2. > > PCI-PM L1.2 may still be used because it doesn't depend on > LTR_L1.2_THRESHOLD (see PCIe r4.0, sec 5.5.1). > > Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > --- > drivers/pci/pcie/aspm.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c > index f76eb7704f64..c687c817b47d 100644 > --- a/drivers/pci/pcie/aspm.c > +++ b/drivers/pci/pcie/aspm.c > @@ -400,6 +400,15 @@ static void pcie_get_aspm_reg(struct pci_dev *pdev, > info->l1ss_cap = 0; > return; > } > + > + /* > + * If we don't have LTR for the entire path from the Root Complex > + * to this device, we can't use ASPM L1.2 because it relies on the > + * LTR_L1.2_THRESHOLD. See PCIe r4.0, secs 5.5.4, 6.18. > + */ > + if (!pdev->ltr_path) > + info->l1ss_cap &= ~PCI_L1SS_CAP_ASPM_L1_2; > + > pci_read_config_dword(pdev, info->l1ss_cap_ptr + PCI_L1SS_CTL1, > &info->l1ss_ctl1); > pci_read_config_dword(pdev, info->l1ss_cap_ptr + PCI_L1SS_CTL2, > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
