On Wed, Jul 27, 2022 at 09:32:51AM +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. > > [1] https://lore.kernel.org/linux-pci/20220408153159.106741-1-kai.heng.feng@xxxxxxxxxxxxx/ > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216295 > > Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> > --- > 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); aer_disable_rootport() seems like it might be overkill. IIUC, what we want to do here is disable AER interrupts, which should only require clearing ROOT_PORT_INTR_ON_MESG_MASK in PCI_ERR_ROOT_COMMAND. In addition to clearing ROOT_PORT_INTR_ON_MESG_MASK, aer_disable_rootport() traverses the whole hierarchy, clearing PCI_EXP_AER_FLAGS (CERE | NFERE | FERE | URRE) in PCI_EXP_DEVCTL. I don't think these DEVCTL bits control interrupt generation, so I don't know why we need to touch them. aer_disable_rootport() also clears PCI_ERR_ROOT_STATUS, which I think we should not do during suspend either. We might want to clear it on resume (which we already do in pci_restore_state()), but I think generally we should preserve error information as long as it doesn't cause trouble. Your thoughts please :) > + > + 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 >
