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Commit f41f064c authored by Yinghai Lu's avatar Yinghai Lu Committed by Linus Torvalds
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PCI: Workaround missing pci_set_master in pci drivers 



Ben Herrenschmidt found that commit 928bea96 ("PCI: Delay enabling
bridges until they're needed") breaks PCI in some powerpc environments.

The reason is that the PCIe port driver will call pci_enable_device() on
the bridge, so the device is enabled, but skips pci_set_master because
pcie_port_auto and no acpi on powerpc.

Because of that, pci_enable_bridge() later on (called as a result of the
child device driver doing pci_enable_device) will see the bridge as
already enabled and will not call pci_set_master() on it.

Fixed by add checking in pci_enable_bridge, and call pci_set_master
if driver skip that.

That will make the code more robot and wade off problem for missing
pci_set_master in drivers.

Reported-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent aeebc264

drivers/pci/pci.c

+7 −1
Original line number Diff line number Diff line
@@ -1155,8 +1155,14 @@ static void pci_enable_bridge(struct pci_dev *dev) 


	pci_enable_bridge(dev->bus->self);



	if (pci_is_enabled(dev))

	if (pci_is_enabled(dev)) {

		if (!dev->is_busmaster) {

			dev_warn(&dev->dev, "driver skip pci_set_master, fix it!\n");

			pci_set_master(dev);

		}

		return;

	}



	retval = pci_enable_device(dev);

	if (retval)

		dev_err(&dev->dev, "Error enabling bridge (%d), continuing\n",