[PATCH] PCI: Add PCI quirk to disable L0s ASPM state for RTL8125 2.5GbE Controller

[hans.zhang@cixtech.com]

From: Hans Zhang <hans.zhang@cixtech.com>

This patch is intended to disable L0s ASPM link state for RTL8125 2.5GbE
Controller due to the fact that it is possible to corrupt TX data when
coming back out of L0s on some systems. This quirk uses the ASPM api to
prevent the ASPM subsystem from re-enabling the L0s state.

And it causes the following AER errors:
  pcieport 0003:30:00.0: AER: Multiple Corrected error received: 0003:31:00.0
  pcieport 0003:30:00.0: PCIe Bus Error: severity=Corrected, type=Data Link Layer, (Transmitter ID)
  pcieport 0003:30:00.0:   device [1f6c:0001] error status/mask=00001000/0000e000
  pcieport 0003:30:00.0:    [12] Timeout
  r8125 0003:31:00.0: PCIe Bus Error: severity=Corrected, type=Data Link Layer, (Transmitter ID)
  r8125 0003:31:00.0:   device [10ec:8125] error status/mask=00001000/0000e000
  r8125 0003:31:00.0:    [12] Timeout
  r8125 0003:31:00.0: AER:   Error of this Agent is reported first

And the RTL8125 website does not say that it supports L0s. It only supports
L1 and L1ss.

RTL8125 website: https://www.realtek.com/Product/Index?id=3962

Signed-off-by: Hans Zhang <hans.zhang@cixtech.com>
Reviewed-by: Peter Chen <peter.chen@cixtech.com>
---
 drivers/pci/quirks.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 82b21e34c545..5f69bb5ee3ff 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -2514,6 +2514,12 @@ 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);
 
+/*
+ * The RTL8125 may experience data corruption issues when transitioning out
+ * of L0S. To prevent this we need to disable L0S on the PCIe link.
+ */
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_REALTEK, 0x8125, quirk_disable_aspm_l0s);
+
 static void quirk_disable_aspm_l0s_l1(struct pci_dev *dev)
 {
 	pci_info(dev, "Disabling ASPM L0s/L1\n");

base-commit: 99fa936e8e4f117d62f229003c9799686f74cebc
-- 
2.47.1