Re: [PATCH v4 2/3] PCI/AER: Disable AER interrupt on suspend
From: Bjorn Helgaas <helgaas@kernel.org>
Date: 2023-05-05 19:22:16
Also in:
linux-pci, lkml
On Mon, Apr 24, 2023 at 01:52:48PM +0800, Kai-Heng Feng wrote:
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.
What is the reason? I assume it's something to do with the bugzilla below, but the commit log should outline the user-visible problem this fixes. The commit log basically makes the case for "why should we merge this patch." I assume it's along the lines of "I tried to suspend this system, but it immediately woke up again because of an AER interrupt, and disabling AER during suspend avoids this problem. And disabling the AER interrupt is not a problem because X"
quoted hunk ↗ jump to hunk
[1] https://lore.kernel.org/linux-pci/20220408153159.106741-1-kai.heng.feng@canonical.com/ (local) Link: https://bugzilla.kernel.org/show_bug.cgi?id=216295 Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Kai-Heng Feng <redacted> --- drivers/pci/pcie/aer.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c index 1420e1f27105..9c07fdbeb52d 100644 --- a/drivers/pci/pcie/aer.c +++ b/drivers/pci/pcie/aer.c@@ -1356,6 +1356,26 @@ 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); + struct pci_dev *pdev = rpc->rpd; + + aer_disable_irq(pdev); + + return 0; +} + +static int aer_resume(struct pcie_device *dev) +{ + struct aer_rpc *rpc = get_service_data(dev); + struct pci_dev *pdev = rpc->rpd; + + aer_enable_irq(pdev); + + return 0; +} + /** * aer_root_reset - reset Root Port hierarchy, RCEC, or RCiEP * @dev: pointer to Root Port, RCEC, or RCiEP@@ -1420,6 +1440,8 @@ static struct pcie_port_service_driver aerdriver = { .service = PCIE_PORT_SERVICE_AER, .probe = aer_probe, + .suspend = aer_suspend, + .resume = aer_resume, .remove = aer_remove, };-- 2.34.1