Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | Subject | Re: [PATCH] More PCI fixes for 2.6.0-test2 | From | Greg KH <> | Date | Fri, 8 Aug 2003 17:32:14 -0700 |
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ChangeSet 1.1119.1.4, 2003/08/08 17:03:19-07:00, ink@jurassic.park.msu.ru
[PATCH] PCI: pci_enable_device vs bridges bugs
Bug #1 (found by Jay Estabrook). On Alpha, under certain circumstances the firmware may close the IO window of PCI-to-PCI bridge even if there is IO behind. This wouldn't be a problem - linux PCI setup code does set up this window properly, but in addition the firmware clears the IO-enable bit in the PCI_COMMAND register of the bridge. Since we don't call pci_enable_* routines for bridges in non-hotplug path, we end up with disabled IO. Fixed by adding pci_enable_bridges() to pci_assign_unassigned_resources(). Architectures which don't use the latter, but do use other setup-bus code (parisc?) also should call pci_enable_bridges() for each root bus.
Bug #2 (closely related to #1). As it turns out, pci_enable_device() doesn't work for bridges at all, only for regular devices (header type 0) due to 0x3f mask passed to pci_enable_device_bars(). The mask should be (1 << PCI_NUM_RESOURCES) - 1.
Bug #3 (quite a few archs, including i386). pcibios_enable_device() does only check first 6 resources (regardless of the mask) to decide whether or not to enable IO and MEM. Bridge resources start at 7.
#2 and #3 affect hotplug. I wonder, has anybody ever tried *bridged* PCI card behind a hot-plug controller?
drivers/pci/pci.c | 2 +- drivers/pci/setup-bus.c | 4 +++- 2 files changed, 4 insertions(+), 2 deletions(-)
diff -Nru a/drivers/pci/pci.c b/drivers/pci/pci.c --- a/drivers/pci/pci.c Fri Aug 8 17:25:03 2003 +++ b/drivers/pci/pci.c Fri Aug 8 17:25:03 2003 @@ -359,7 +359,7 @@ int pci_enable_device(struct pci_dev *dev) { - return pci_enable_device_bars(dev, 0x3F); + return pci_enable_device_bars(dev, (1 << PCI_NUM_RESOURCES) - 1); } /** diff -Nru a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c --- a/drivers/pci/setup-bus.c Fri Aug 8 17:25:03 2003 +++ b/drivers/pci/setup-bus.c Fri Aug 8 17:25:03 2003 @@ -530,6 +530,8 @@ for(ln=pci_root_buses.next; ln != &pci_root_buses; ln=ln->next) pci_bus_size_bridges(pci_bus_b(ln)); /* Depth last, allocate resources and update the hardware. */ - for(ln=pci_root_buses.next; ln != &pci_root_buses; ln=ln->next) + for(ln=pci_root_buses.next; ln != &pci_root_buses; ln=ln->next) { pci_bus_assign_resources(pci_bus_b(ln)); + pci_enable_bridges(pci_bus_b(ln)); + } } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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