From: Kai-Heng Feng <kai.heng.f...@canonical.com> If the link is powered off during suspend, electrical noise may cause errors that trigger DPC. If the DPC interrupt is enabled and shares an IRQ with PME, that causes a spurious wakeup during suspend.
Disable DPC triggering and the DPC interrupt during suspend to prevent this. Clear DPC interrupt status before re-enabling DPC interrupts during resume so we don't get an interrupt for errors that occurred during the suspend/resume process. Link: https://bugzilla.kernel.org/show_bug.cgi?id=209149 Link: https://bugzilla.kernel.org/show_bug.cgi?id=216295 Link: https://bugzilla.kernel.org/show_bug.cgi?id=218090 Link: https://lore.kernel.org/r/20240416043225.1462548-3-kai.heng.f...@canonical.com Signed-off-by: Kai-Heng Feng <kai.heng.f...@canonical.com> [bhelgaas: clear status on resume, add comments, commit log] Signed-off-by: Bjorn Helgaas <bhelg...@google.com> --- drivers/pci/pcie/dpc.c | 60 +++++++++++++++++++++++++++++++++--------- 1 file changed, 48 insertions(+), 12 deletions(-) diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c index a668820696dc..2b6ef7efa3c1 100644 --- a/drivers/pci/pcie/dpc.c +++ b/drivers/pci/pcie/dpc.c @@ -412,13 +412,44 @@ void pci_dpc_init(struct pci_dev *pdev) } } +static void dpc_enable(struct pcie_device *dev) +{ + struct pci_dev *pdev = dev->port; + int dpc = pdev->dpc_cap; + u16 ctl; + + /* + * Clear DPC Interrupt Status so we don't get an interrupt for an + * old event when setting DPC Interrupt Enable. + */ + pci_write_config_word(pdev, dpc + PCI_EXP_DPC_STATUS, + PCI_EXP_DPC_STATUS_INTERRUPT); + + pci_read_config_word(pdev, dpc + PCI_EXP_DPC_CTL, &ctl); + ctl &= ~PCI_EXP_DPC_CTL_EN_MASK; + ctl |= PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN; + pci_write_config_word(pdev, dpc + PCI_EXP_DPC_CTL, ctl); +} + +static void dpc_disable(struct pcie_device *dev) +{ + struct pci_dev *pdev = dev->port; + int dpc = pdev->dpc_cap; + u16 ctl; + + /* Disable DPC triggering and DPC interrupts */ + pci_read_config_word(pdev, dpc + PCI_EXP_DPC_CTL, &ctl); + ctl &= ~(PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN); + pci_write_config_word(pdev, dpc + PCI_EXP_DPC_CTL, ctl); +} + #define FLAG(x, y) (((x) & (y)) ? '+' : '-') static int dpc_probe(struct pcie_device *dev) { struct pci_dev *pdev = dev->port; struct device *device = &dev->device; int status; - u16 ctl, cap; + u16 cap; if (!pcie_aer_is_native(pdev) && !pcie_ports_dpc_native) return -ENOTSUPP; @@ -433,11 +464,7 @@ static int dpc_probe(struct pcie_device *dev) } pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CAP, &cap); - - pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, &ctl); - ctl &= ~PCI_EXP_DPC_CTL_EN_MASK; - ctl |= PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN; - pci_write_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, ctl); + dpc_enable(dev); pci_info(pdev, "enabled with IRQ %d\n", dev->irq); pci_info(pdev, "error containment capabilities: Int Msg #%d, RPExt%c PoisonedTLP%c SwTrigger%c RP PIO Log %d, DL_ActiveErr%c\n", @@ -450,14 +477,21 @@ static int dpc_probe(struct pcie_device *dev) return status; } +static int dpc_suspend(struct pcie_device *dev) +{ + dpc_disable(dev); + return 0; +} + +static int dpc_resume(struct pcie_device *dev) +{ + dpc_enable(dev); + return 0; +} + static void dpc_remove(struct pcie_device *dev) { - struct pci_dev *pdev = dev->port; - u16 ctl; - - pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, &ctl); - ctl &= ~(PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN); - pci_write_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, ctl); + dpc_disable(dev); } static struct pcie_port_service_driver dpcdriver = { @@ -465,6 +499,8 @@ static struct pcie_port_service_driver dpcdriver = { .port_type = PCIE_ANY_PORT, .service = PCIE_PORT_SERVICE_DPC, .probe = dpc_probe, + .suspend = dpc_suspend, + .resume = dpc_resume, .remove = dpc_remove, }; -- 2.34.1
