On Mon, Aug 9, 2021 at 5:47 PM Lukas Wunner <lukas@xxxxxxxxx> wrote: > > [cc += Mika] > > On Mon, Aug 09, 2021 at 12:24:12PM +0800, Kai-Heng Feng wrote: > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=213873 > > The last comment on this bugzilla says "BIOS will fix this." > and the status is RESOLVED WILL_NOT_FIX. > > Why is the patch still necessary? Well, let me update the bug report. > > > > Some platforms cannot detect ethernet hotplug once its upstream port is > > runtime suspended because PME isn't enabled in _OSC. > > If PME is not handled natively, why does the NIC runtime suspend? > Shouldn't this be fixed in the NIC driver by keeping the device > runtime active if PME cannot be used? That means we need to fix every user of pci_dev_run_wake(), or fix the issue in pci_dev_run_wake() helper itself. However, I am afraid that implementing the fix in pci_dev_run_wake() may break the while loop check: bool pci_dev_run_wake(struct pci_dev *dev) { ... while (bus->parent) { struct pci_dev *bridge = bus->self; if (device_can_wakeup(&bridge->dev)) return true; bus = bus->parent; ... } So I took the current approach. > > > > Disallow port runtime suspend when any child device requires wakeup, so > > pci_pme_list_scan() can still read the PME status from the devices > > behind the port. > > pci_pme_list_scan() is for broken devices which fail to signal PME. > Is this NIC really among them or does PME fail merely because it's not > granted to OSPM? The latter, PME IRQ isn't enabled because it's not granted by BIOS _OSC. > > > > --- a/drivers/pci/pcie/portdrv_pci.c > > +++ b/drivers/pci/pcie/portdrv_pci.c > > @@ -59,14 +59,30 @@ static int pcie_port_runtime_suspend(struct device *dev) > > return pcie_port_device_runtime_suspend(dev); > > } > > > > +static int pcie_port_wakeup_check(struct device *dev, void *data) > > +{ > > + struct pci_dev *pdev = to_pci_dev(dev); > > + > > + if (!pdev) > > + return 0; > > + > > + return pdev->wakeup_prepared; > > +} > > + > > static int pcie_port_runtime_idle(struct device *dev) > > { > > + struct pci_dev *pdev = to_pci_dev(dev); > > + > > + if (!pcie_port_find_device(pdev, PCIE_PORT_SERVICE_PME) && > > + device_for_each_child(dev, NULL, pcie_port_wakeup_check)) > > + return -EBUSY; > > + > > /* > > * Assume the PCI core has set bridge_d3 whenever it thinks the port > > * should be good to go to D3. Everything else, including moving > > * the port to D3, is handled by the PCI core. > > */ > > - return to_pci_dev(dev)->bridge_d3 ? 0 : -EBUSY; > > + return pdev->bridge_d3 ? 0 : -EBUSY; > > If an additional check is necessary for this issue, it should be > integrated into pci_dev_check_d3cold() instead of pcie_port_runtime_idle(). I think PME IRQ and D3cold are different things here. The root port of the affected NIC doesn't support D3cold because there's no power resource. Kai-Heng > > Thanks, > > Lukas
