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authorYinghai Lu <yinghai@kernel.org>2013-11-05 13:34:38 -0700
committerBjorn Helgaas <bhelgaas@google.com>2013-11-05 16:36:02 -0700
commitcf3e1feba7f906f233790f1806592730a88f584d (patch)
treef078aab6108d10ffe9f8859967fbb30b8aa8bf71
parent6b87e700cd65120b70aaa097a8f4e7f22f1945ee (diff)
downloadop-kernel-dev-cf3e1feba7f906f233790f1806592730a88f584d.zip
op-kernel-dev-cf3e1feba7f906f233790f1806592730a88f584d.tar.gz
PCI: Workaround missing pci_set_master in pci drivers
Ben Herrenschmidt found that commit 928bea964827 ("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: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/pci/pci.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 36cc8d5..7a92d81 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -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",
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