PCI/ASPM: Convert quirks to override advertised link states

Existing quirks to disable ASPM L0s and L1 use pci_disable_link_state(),
which disables ASPM states and prevents their use in the future.  But since
they are FINAL quirks, they happen after ASPM has already been enabled.
Here's a typical call path:

  pci_host_probe
    pci_scan_root_bus_bridge
      pci_scan_child_bus
        pci_scan_slot
          pci_scan_single_device
            pci_device_add
              pci_fixup_device(pci_fixup_header)  # HEADER quirks
          pcie_aspm_init_link_state
            pcie_config_aspm_path
              pcie_config_aspm_link
                pcie_config_aspm_dev              # ASPM may be enabled
    pci_bus_add_devices
      pci_bus_add_devices
        pci_fixup_device(pci_fixup_final)         # FINAL quirks
          quirk_disable_aspm_l0s
            pci_disable_link_state(dev, PCIE_LINK_STATE_L0S)

Sometimes enabling ASPM can make the link non-functional, so if we know
ASPM is broken on a device, we shouldn't enable it at all, even
temporarily.

Convert the existing quirks to use pcie_aspm_remove_cap() instead, which
overrides the ASPM Support advertised in PCIe Link Capabilities, and make
them HEADER quirks so they run before pcie_aspm_init_link_state() has a
chance to enable ASPM.

Signed-off-by: Bjorn Helgaas <[email protected]>
Tested-by: Shawn Lin <[email protected]>
Reviewed-by: Lukas Wunner <[email protected]>
Link: https://patch.msgid.link/[email protected]

Author: bjorn-helgaas

drivers/pci/quirks.c

@@ -2494,36 +2494,35 @@ DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_INTEL, PCI_ANY_ID,
  */
 static void quirk_disable_aspm_l0s(struct pci_dev *dev)
 {
-	pci_info(dev, "Disabling L0s\n");
-	pci_disable_link_state(dev, PCIE_LINK_STATE_L0S);
-}
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x10a7, quirk_disable_aspm_l0s);
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x10a9, quirk_disable_aspm_l0s);
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x10b6, quirk_disable_aspm_l0s);
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x10c6, quirk_disable_aspm_l0s);
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x10c7, quirk_disable_aspm_l0s);
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x10c8, quirk_disable_aspm_l0s);
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x10d6, quirk_disable_aspm_l0s);
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x10db, quirk_disable_aspm_l0s);
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x10dd, quirk_disable_aspm_l0s);
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x10e1, quirk_disable_aspm_l0s);
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x10ec, quirk_disable_aspm_l0s);
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x10f1, quirk_disable_aspm_l0s);
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x10f4, quirk_disable_aspm_l0s);
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x1508, quirk_disable_aspm_l0s);
+	pcie_aspm_remove_cap(dev, PCI_EXP_LNKCAP_ASPM_L0S);
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x10a7, quirk_disable_aspm_l0s);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x10a9, quirk_disable_aspm_l0s);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x10b6, quirk_disable_aspm_l0s);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x10c6, quirk_disable_aspm_l0s);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x10c7, quirk_disable_aspm_l0s);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x10c8, quirk_disable_aspm_l0s);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x10d6, quirk_disable_aspm_l0s);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x10db, quirk_disable_aspm_l0s);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x10dd, quirk_disable_aspm_l0s);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x10e1, quirk_disable_aspm_l0s);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x10ec, quirk_disable_aspm_l0s);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x10f1, quirk_disable_aspm_l0s);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x10f4, quirk_disable_aspm_l0s);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x1508, quirk_disable_aspm_l0s);
 
 static void quirk_disable_aspm_l0s_l1(struct pci_dev *dev)
 {
-	pci_info(dev, "Disabling ASPM L0s/L1\n");
-	pci_disable_link_state(dev, PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1);
+	pcie_aspm_remove_cap(dev,
+			     PCI_EXP_LNKCAP_ASPM_L0S | PCI_EXP_LNKCAP_ASPM_L1);
 }
 
 /*
  * ASM1083/1085 PCIe-PCI bridge devices cause AER timeout errors on the
  * upstream PCIe root port when ASPM is enabled. At least L0s mode is affected;
  * disable both L0s and L1 for now to be safe.
  */
-DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ASMEDIA, 0x1080, quirk_disable_aspm_l0s_l1);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_ASMEDIA, 0x1080, quirk_disable_aspm_l0s_l1);
 
 /*
  * Some Pericom PCIe-to-PCI bridges in reverse mode need the PCIe Retrain