Messages in this thread | | | From | Andy Shevchenko <> | Date | Sat, 12 Oct 2019 10:34:35 +0300 | Subject | Re: [PATCH v2 2/3] PCI: pciehp: Wait for PDS if in-band presence is disabled |
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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) ?
> +}
-- With Best Regards, Andy Shevchenko
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