Commit 9f982756 authored Aug 29, 2017 by Bjorn Helgaas

PCI: Always check for non-CRS response before timeout



While waiting for a device to become ready (i.e., to return a non-CRS
completion to a read of its Vendor ID), if we got a valid response to the
very last read before timing out, we printed a warning and gave up on the
device even though it was actually ready.

For a typical 60s timeout, we wait about 65s (it's not exact because of the
exponential backoff), but we treated devices that became ready between 33s
and 65s as though they failed.

Move the Device ID read later so we check whether the device is ready
before checking for a timeout.

Thanks to Sinan Kaya <okaya@codeaurora.org>, reorder reads so we always
check device presence after sleep, since it's pointless to sleep unless we
recheck afterwards.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

parent 40f11adc

drivers/pci/probe.c

+6 −5

Original line number	Diff line number	Diff line
		@@ -1876,17 +1876,18 @@ bool pci_bus_read_dev_vendor_id(struct pci_bus bus, int devfn, u32 l,
		if (!crs_timeout)
		return false;

		msleep(delay);
		delay *= 2;
		if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, l))
		return false;
		/* Card hasn't responded in 60 seconds? Must be stuck. */
		if (delay > crs_timeout) {
		printk(KERN_WARNING "pci %04x:%02x:%02x.%d: not responding\n",
		pci_domain_nr(bus), bus->number, PCI_SLOT(devfn),
		PCI_FUNC(devfn));
		return false;
		}

		msleep(delay);
		delay *= 2;

		if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, l))
		return false;
		}

		return true;

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