Patch "PCI: Avoid bus reset if bridge itself is broken" has been added to the 4.4-stable tree

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;a=summary

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 <[email protected]> know about it.

From: David Daney <[email protected]>
Date: Fri, 8 Sep 2017 10:10:31 +0200
Subject: PCI: Avoid bus reset if bridge itself is broken

From: David Daney <[email protected]>

[ 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.

---
 drivers/pci/pci.c |    4 ++++
 1 file changed, 4 insertions(+)

@@ -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 [email protected] are

queue-4.4/pci-avoid-bus-reset-if-bridge-itself-is-broken.patch