This is a note to let you know that I've just added the patch titled
PCI: Avoid bus reset if bridge itself is broken
to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: pci-avoid-bus-reset-if-bridge-itself-is-broken.patch and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Thu Dec 21 10:35:49 CET 2017
From: David Daney david.daney@cavium.com Date: Fri, 8 Sep 2017 10:10:31 +0200 Subject: PCI: Avoid bus reset if bridge itself is broken
From: David Daney david.daney@cavium.com
[ Upstream commit 357027786f3523d26f42391aa4c075b8495e5d28 ]
When checking to see if a PCI bus can safely be reset, we previously checked to see if any of the children had their PCI_DEV_FLAGS_NO_BUS_RESET flag set. Children marked with that flag are known not to behave well after a bus reset.
Some PCIe root port bridges also do not behave well after a bus reset, sometimes causing the devices behind the bridge to become unusable.
Add a check for PCI_DEV_FLAGS_NO_BUS_RESET being set in the bridge device to allow these bridges to be flagged, and prevent their secondary buses from being reset.
Signed-off-by: David Daney david.daney@cavium.com [jglauber@cavium.com: fixed typo] Signed-off-by: Jan Glauber jglauber@cavium.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com Reviewed-by: Alex Williamson alex.williamson@redhat.com
Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/pci/pci.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3850,6 +3850,10 @@ static bool pci_bus_resetable(struct pci { struct pci_dev *dev;
+ + if (bus->self && (bus->self->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET)) + return false; + list_for_each_entry(dev, &bus->devices, bus_list) { if (dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET || (dev->subordinate && !pci_bus_resetable(dev->subordinate)))
Patches currently in stable-queue which might be from david.daney@cavium.com are
queue-4.4/pci-avoid-bus-reset-if-bridge-itself-is-broken.patch