[SRU][R][PATCH 3/3] PCI/ASPM: Convert quirks to override advertised link states

[AceLan Kao]

From: Bjorn Helgaas <bhelgaas at google.com>

BugLink: https://bugs.launchpad.net/bugs/2166737

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 <bhelgaas at google.com>
Tested-by: Shawn Lin <shawn.lin at rock-chips.com>
Reviewed-by: Lukas Wunner <lukas at wunner.de>
Link: https://patch.msgid.link/20251110222929.2140564-4-helgaas@kernel.org
(cherry picked from commit 30579eebba6ae52dc7441479aec9dd8d782256d3)
Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao at canonical.com>
---
 drivers/pci/quirks.c | 39 +++++++++++++++++++--------------------
 1 file changed, 19 insertions(+), 20 deletions(-)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index f1419d14d169c..ea77e64edc869 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -2511,31 +2511,30 @@ 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);
 
 /* Realtek RTS525A generates a Replay Timer Timeout storm when L0s is enabled. */
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_REALTEK, 0x525a, 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);
 }
 
 /*
@@ -2543,7 +2542,7 @@ static void quirk_disable_aspm_l0s_l1(struct pci_dev *dev)
  * 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
-- 
2.53.0