[PATCH net] igc: Disable PCIe L1.2 substate on I225-LMvP and I226-LMvP devices

["Daniel Viaño" <danividanivi@gmail.com>]

Commit 0325143b59c6 ("igc: disable L1.2 PCI-E link substate to avoid
performance issue") disabled the L1.2 substate on I226 controllers due
to hardware exit latency limitations. However, IGC_DEV_ID_I226_LMVP
(0x5503) was omitted from igc_is_device_id_i226(), and IGC_DEV_ID_I225_LMVP
(0x5502) exhibits the same L1.2 exit latency constraints.

On systems where I225-LMvP is connected behind Thunderbolt/USB4 bridges
(such as the HP Thunderbolt Dock G4), negotiating L1.2 triggers severe
BadDLLP packet framing errors, link timeouts, and system hangs during
shutdown. An earlier attempt ("igc: Mask replay rollover/timeout errors
in I225_LMVP") proposed masking AER reporting. However, as Bjorn
Helgaas noted in review of that patch, simply masking errors is
undesirable and fixing the root cause is preferable; disabling L1.2
prevents the link from entering the unstable substate entirely.

Include IGC_DEV_ID_I226_LMVP in igc_is_device_id_i226() and disable the
L1.2 substate for I225-LMvP across probe, resume, and error recovery to
ensure link stability without masking AER errors.

Fixes: 0325143b59c6 ("igc: disable L1.2 PCI-E link substate to avoid performance issue")
Link: https://lore.kernel.org/lkml/eb5a9805-3e53-ec22-696e-21c6b8cf0bfc@molgen.mpg.de/T/
Signed-off-by: Daniel Viaño <danividanivi@gmail.com>
---
 drivers/net/ethernet/intel/igc/igc_base.c | 1 +
 drivers/net/ethernet/intel/igc/igc_main.c | 8 ++++----
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc_base.c b/drivers/net/ethernet/intel/igc/igc_base.c
index ab9120a3127f..6865fef4049f 100644
--- a/drivers/net/ethernet/intel/igc/igc_base.c
+++ b/drivers/net/ethernet/intel/igc/igc_base.c
@@ -447,6 +447,7 @@ bool igc_is_device_id_i226(struct igc_hw *hw)
 	case IGC_DEV_ID_I226_V:
 	case IGC_DEV_ID_I226_K:
 	case IGC_DEV_ID_I226_IT:
+	case IGC_DEV_ID_I226_LMVP:
 		return true;
 	default:
 		return false;
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 1fb5f3cbe93c..6c4e04661068 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -7172,8 +7172,8 @@ static int igc_probe(struct pci_dev *pdev,
 	hw->subsystem_vendor_id = pdev->subsystem_vendor;
 	hw->subsystem_device_id = pdev->subsystem_device;
 
-	/* Disable ASPM L1.2 on I226 devices to avoid packet loss */
-	if (igc_is_device_id_i226(hw))
+	/* Disable ASPM L1.2 on I226 and I225-LMvP devices to avoid packet loss */
+	if (igc_is_device_id_i226(hw) || hw->device_id == IGC_DEV_ID_I225_LMVP)
 		pci_disable_link_state(pdev, PCIE_LINK_STATE_L1_2);
 
 	err = pci_save_state(pdev);
@@ -7559,7 +7559,7 @@ static int __igc_resume(struct device *dev, bool rpm)
 	pci_enable_wake(pdev, PCI_D3hot, 0);
 	pci_enable_wake(pdev, PCI_D3cold, 0);
 
-	if (igc_is_device_id_i226(hw))
+	if (igc_is_device_id_i226(hw) || hw->device_id == IGC_DEV_ID_I225_LMVP)
 		pci_disable_link_state(pdev, PCIE_LINK_STATE_L1_2);
 
 	if (igc_init_interrupt_scheme(adapter, true)) {
@@ -7688,7 +7688,7 @@ static pci_ers_result_t igc_io_slot_reset(struct pci_dev *pdev)
 		pci_enable_wake(pdev, PCI_D3hot, 0);
 		pci_enable_wake(pdev, PCI_D3cold, 0);
 
-		if (igc_is_device_id_i226(hw))
+		if (igc_is_device_id_i226(hw) || hw->device_id == IGC_DEV_ID_I225_LMVP)
 			pci_disable_link_state_locked(pdev, PCIE_LINK_STATE_L1_2);
 
 		/* In case of PCI error, adapter loses its HW address
-- 
2.53.0