[PATCH] PCI: Workaround missing pci_set_master in pci drivers

From: Yinghai Lu
Date: Sat Sep 28 2013 - 16:13:27 EST

BenH found:
| 928bea964827d7824b548c1f8e06eccbbc4d0d7d
| PCI: Delay enabling bridges until they're needed

break PCI on powerpc. The reason is that the PCIe port driver will
call pci_enable_device() on the bridge, so device enabled (but skip
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: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>

drivers/pci/pci.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

Index: linux-2.6/drivers/pci/pci.c
--- linux-2.6.orig/drivers/pci/pci.c
+++ linux-2.6/drivers/pci/pci.c
@@ -1156,8 +1156,14 @@ static void pci_enable_bridge(struct pci


- 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);
+ }
+ }
retval = pci_enable_device(dev);
if (retval)
dev_err(&dev->dev, "Error enabling bridge (%d), continuing\n",
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