| Message ID | 20191011205127.4884-3-stuart.w.hayes@gmail.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | PCI: pciehp: Do not turn off slot if presence comes up after link | expand |
On Fri, Oct 11, 2019 at 11:51 PM Stuart Hayes <stuart.w.hayes@gmail.com> wrote: > > From: Alexandru Gagniuc <mr.nuke.me@gmail.com> > > When inband presence is disabled, PDS may come up at any time, or not > at all. PDS being low may indicate that the card is still mating, and > we could expect contact bounce to bring down the link as well. > > It is reasonable to assume that most cards will mate in a hotplug slot > in about a second. Thus, when we know PDS only reflects out-of-band > presence, it's worthwhile to wait the extra second or so to make sure > the card is properly mated before loading the driver, and to prevent > the hotplug code from disabling a device if the presence detect change > goes active after the device is enabled. Thank you! My comments below. > +static void pcie_wait_for_presence(struct pci_dev *pdev) > +{ > + int timeout = 1250; > + bool pds; make W=1 will issue a warning. Just remove the line. > + u16 slot_status; > + > + do { > + pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status); > + if (!!(slot_status & PCI_EXP_SLTSTA_PDS)) > + return; > + msleep(10); > + timeout -= 10; > + } while (timeout > 0); > + > + pci_info(pdev, "Presence Detect state not set in 1250 msec\n"); Perhaps ("%d", timeout) ? > +}
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index dc109d521f30..db5c7b082fda 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -242,6 +242,23 @@ static bool pci_bus_check_dev(struct pci_bus *bus, int devfn) return found; } +static void pcie_wait_for_presence(struct pci_dev *pdev) +{ + int timeout = 1250; + bool pds; + u16 slot_status; + + do { + pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status); + if (!!(slot_status & PCI_EXP_SLTSTA_PDS)) + return; + msleep(10); + timeout -= 10; + } while (timeout > 0); + + pci_info(pdev, "Presence Detect state not set in 1250 msec\n"); +} + int pciehp_check_link_status(struct controller *ctrl) { struct pci_dev *pdev = ctrl_dev(ctrl); @@ -251,6 +268,9 @@ int pciehp_check_link_status(struct controller *ctrl) if (!pcie_wait_for_link(pdev, true)) return -1; + if (ctrl->inband_presence_disabled) + pcie_wait_for_presence(pdev); + found = pci_bus_check_dev(ctrl->pcie->port->subordinate, PCI_DEVFN(0, 0));