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SubjectRe: [PATCH v2 2/3] PCI: pciehp: Wait for PDS if in-band presence is disabled
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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