On 4/15/24 9:32 PM, Kai-Heng Feng wrote: > When the power rail gets cut off, the hardware can create some electric > noise on the link that triggers AER. If IRQ is shared between AER with > PME, such AER noise will cause a spurious wakeup on system suspend. > > When the power rail gets back, the firmware of the device resets itself > and can create unexpected behavior like sending PTM messages. For this > case, the driver will always be too late to toggle off features should > be disabled. > > As Per PCIe Base Spec 5.0, section 5.2, titled "Link State Power > Management", TLP and DLLP transmission are disabled for a Link in L2/L3 > Ready (D3hot), L2 (D3cold with aux power) and L3 (D3cold) states. So if > the power will be turned off during suspend process, disable AER service > and re-enable it during the resume process. This should not affect the > basic functionality. > > 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 > Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> > --- Looks good to me. Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> > v8: > - Add more bug reports. > > v7: > - Wording > - Disable AER completely (again) if power will be turned off > > v6: > v5: > - Wording. > > v4: > v3: > - No change. > > v2: > - Only disable AER IRQ. > - No more check on PME IRQ#. > - Use helper. > > drivers/pci/pcie/aer.c | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c > index ac6293c24976..bea7818c2d1b 100644 > --- a/drivers/pci/pcie/aer.c > +++ b/drivers/pci/pcie/aer.c > @@ -28,6 +28,7 @@ > #include <linux/delay.h> > #include <linux/kfifo.h> > #include <linux/slab.h> > +#include <linux/suspend.h> > #include <acpi/apei.h> > #include <acpi/ghes.h> > #include <ras/ras_event.h> > @@ -1497,6 +1498,28 @@ 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; > + > + if (pci_ancestor_pr3_present(pdev) || pm_suspend_via_firmware()) > + aer_disable_rootport(rpc); > + > + return 0; > +} > + > +static int aer_resume(struct pcie_device *dev) > +{ > + struct aer_rpc *rpc = get_service_data(dev); > + struct pci_dev *pdev = rpc->rpd; > + > + if (pci_ancestor_pr3_present(pdev) || pm_resume_via_firmware()) > + aer_enable_rootport(rpc); > + > + return 0; > +} > + > /** > * aer_root_reset - reset Root Port hierarchy, RCEC, or RCiEP > * @dev: pointer to Root Port, RCEC, or RCiEP > @@ -1561,6 +1584,8 @@ static struct pcie_port_service_driver aerdriver = { > .service = PCIE_PORT_SERVICE_AER, > > .probe = aer_probe, > + .suspend = aer_suspend, > + .resume = aer_resume, > .remove = aer_remove, > }; > -- Sathyanarayanan Kuppuswamy Linux Kernel Developer
