linux-kernel - [PATCH 2/3] PCI/AER: Disable AER service on suspend when IRQ is shared with PME

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Message-Id: <20220727013255.269815-2-kai.heng.feng@canonical.com>
Date:   Wed, 27 Jul 2022 09:32:51 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     bhelgaas@...gle.com
Cc:     mika.westerberg@...ux.intel.com, koba.ko@...onical.com,
        sathyanarayanan.kuppuswamy@...ux.intel.com,
        Kai-Heng Feng <kai.heng.feng@...onical.com>,
        Russell Currey <ruscur@...sell.cc>,
        "Oliver O'Halloran" <oohall@...il.com>,
        linuxppc-dev@...ts.ozlabs.org, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] PCI/AER: Disable AER service on suspend when IRQ is shared with PME

PCIe service that shares IRQ with PME may cause spurious wakeup on
system suspend.

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), so we don't lose
much here to disable AER during system suspend.

This is very similar to previous attempts to suspend AER and DPC [1],
but with a different reason.

[1] https://lore.kernel.org/linux-pci/20220408153159.106741-1-kai.heng.feng@canonical.com/
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216295

Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
---
 drivers/pci/pcie/aer.c | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 7952e5efd6cf3..60cc373754af2 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -1372,6 +1372,26 @@ 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);
+
+	if (dev->shared_pme_irq)
+		aer_disable_rootport(rpc);
+
+	return 0;
+}
+
+static int aer_resume(struct pcie_device *dev)
+{
+	struct aer_rpc *rpc = get_service_data(dev);
+
+	if (dev->shared_pme_irq)
+		aer_enable_rootport(rpc);
+
+	return 0;
+}
+
 /**
  * aer_root_reset - reset Root Port hierarchy, RCEC, or RCiEP
  * @dev: pointer to Root Port, RCEC, or RCiEP
@@ -1441,8 +1461,9 @@ static struct pcie_port_service_driver aerdriver = {
 	.name		= "aer",
 	.port_type	= PCIE_ANY_PORT,
 	.service	= PCIE_PORT_SERVICE_AER,
-
 	.probe		= aer_probe,
+	.suspend	= aer_suspend,
+	.resume		= aer_resume,
 	.remove		= aer_remove,
 };
 
-- 
2.36.1