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From:   Kai-Heng Feng <kai.heng.feng@canonical.com>
To:     bhelgaas@google.com
Cc:     mika.westerberg@linux.intel.com, koba.ko@canonical.com,
        baolu.lu@linux.intel.com,
        sathyanarayanan.kuppuswamy@linux.intel.com,
        Kai-Heng Feng <kai.heng.feng@canonical.com>,
        Russell Currey <ruscur@russell.cc>,
        "Oliver O'Halloran" <oohall@gmail.com>,
        linuxppc-dev@lists.ozlabs.org, linux-pci@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH v4 1/2] PCI/AER: Disable AER service when link is in L2/L3 ready, L2 and L3 state
Date:   Fri,  8 Apr 2022 23:31:58 +0800
Message-Id: <20220408153159.106741-1-kai.heng.feng@canonical.com>
MIME-Version: 1.0
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On Intel Alder Lake platforms, Thunderbolt entering D3cold can cause
some errors reported by AER:
[   30.100211] pcieport 0000:00:1d.0: AER: Uncorrected (Non-Fatal) error received: 0000:00:1d.0
[   30.100251] pcieport 0000:00:1d.0: PCIe Bus Error: severity=Uncorrected (Non-Fatal), type=Transaction Layer, (Requester ID)
[   30.100256] pcieport 0000:00:1d.0:   device [8086:7ab0] error status/mask=00100000/00004000
[   30.100262] pcieport 0000:00:1d.0:    [20] UnsupReq               (First)
[   30.100267] pcieport 0000:00:1d.0: AER:   TLP Header: 34000000 08000052 00000000 00000000
[   30.100372] thunderbolt 0000:0a:00.0: AER: can't recover (no error_detected callback)
[   30.100401] xhci_hcd 0000:3e:00.0: AER: can't recover (no error_detected callback)
[   30.100427] pcieport 0000:00:1d.0: AER: device recovery failed

So disable AER service to avoid the noises from turning power rails
on/off when the device is in low power states (D3hot and D3cold), as
PCIe Base Spec 5.0, section 5.2 "Link State Power Management" states
that TLP and DLLP transmission is disabled for a Link in L2/L3 Ready
(D3hot), L2 (D3cold with aux power) and L3 (D3cold).

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215453
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
v4:
 - Explicitly states the spec version.
 - Wording change. 

v3:
 - Remove reference to ACS.
 - Wording change.

v2:
 - Wording change.

 drivers/pci/pcie/aer.c | 31 +++++++++++++++++++++++++------
 1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 9fa1f97e5b270..e4e9d4a3098d7 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -1367,6 +1367,22 @@ static int aer_probe(struct pcie_device *dev)
 	return 0;
 }
 
+static int aer_suspend(struct pcie_device *dev)
+{
+	struct aer_rpc *rpc = get_service_data(dev);
+
+	aer_disable_rootport(rpc);
+	return 0;
+}
+
+static int aer_resume(struct pcie_device *dev)
+{
+	struct aer_rpc *rpc = get_service_data(dev);
+
+	aer_enable_rootport(rpc);
+	return 0;
+}
+
 /**
  * aer_root_reset - reset Root Port hierarchy, RCEC, or RCiEP
  * @dev: pointer to Root Port, RCEC, or RCiEP
@@ -1433,12 +1449,15 @@ static pci_ers_result_t aer_root_reset(struct pci_dev *dev)
 }
 
 static struct pcie_port_service_driver aerdriver = {
-	.name		= "aer",
-	.port_type	= PCIE_ANY_PORT,
-	.service	= PCIE_PORT_SERVICE_AER,
-
-	.probe		= aer_probe,
-	.remove		= aer_remove,
+	.name			= "aer",
+	.port_type		= PCIE_ANY_PORT,
+	.service		= PCIE_PORT_SERVICE_AER,
+	.probe			= aer_probe,
+	.suspend		= aer_suspend,
+	.resume			= aer_resume,
+	.runtime_suspend	= aer_suspend,
+	.runtime_resume		= aer_resume,
+	.remove			= aer_remove,
 };
 
 /**
-- 
2.34.1