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Merge branch 'pci/aspm'

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- disable ASPM L1.2 substate if we don't have LTR (Bjorn Helgaas)

  - respect platform ownership of LTR (Bjorn Helgaas)

* pci/aspm:
  PCI/ACPI: Request LTR control from platform before using it
  PCI/ASPM: Disable ASPM L1.2 Substate if we don't have LTR
This commit is contained in:
Bjorn Helgaas
2018-06-06 16:10:05 -05:00
parent d7e02c08a9 af8bb9f898
commit 08b5b2f783
5 changed files with 23 additions and 1 deletions
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9
drivers/pci/pcie/aspm.c
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@@ -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,