Patch "PCI: Apply _HPX settings only to relevant devices" 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: Apply _HPX settings only to relevant devices

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-apply-_hpx-settings-only-to-relevant-devices.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: Bjorn Helgaas <[email protected]>
Date: Mon, 2 Jan 2017 14:04:24 -0600
Subject: PCI: Apply _HPX settings only to relevant devices

From: Bjorn Helgaas <[email protected]>

[ Upstream commit 977509f7c5c6fb992ffcdf4291051af343b91645 ]

Previously we didn't check the type of device before trying to apply Type 1 (PCI-X) or Type 2 (PCIe) Setting Records from _HPX.

We don't support PCI-X Setting Records, so this was harmless, but the warning was useless.

We do support PCIe Setting Records, and we didn't check whether a device was PCIe before applying settings. I don't think anything bad happened on non-PCIe devices because pcie_capability_clear_and_set_word(), pcie_cap_has_lnkctl(), etc., would fail before doing any harm. But it's ugly to depend on those internals.

Check the device type before attempting to apply Type 1 and Type 2 Setting Records (Type 0 records are applicable to PCI, PCI-X, and PCIe devices).

A side benefit is that this prevents useless "not supported" warnings when a BIOS supplies a Type 1 (PCI-X) Setting Record and we try to apply it to every single device:

pci 0000:00:00.0: PCI-X settings not supported

After this patch, we'll get the warning only when a BIOS supplies a Type 1 record and we have a PCI-X device to which it should be applied.

---
 drivers/pci/probe.c |   15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

@@ -1414,8 +1414,16 @@ static void program_hpp_type0(struct pci
 
 static void program_hpp_type1(struct pci_dev *dev, struct hpp_type1 *hpp)
 {
-	if (hpp)
-		dev_warn(&dev->dev, "PCI-X settings not supported\n");
+	int pos;
+
+	if (!hpp)
+		return;
+
+	pos = pci_find_capability(dev, PCI_CAP_ID_PCIX);
+	if (!pos)
+		return;
+
+	dev_warn(&dev->dev, "PCI-X settings not supported\n");
 }
 
 static bool pcie_root_rcb_set(struct pci_dev *dev)

@@ -1441,6 +1449,9 @@ static void program_hpp_type2(struct pci
 	if (!hpp)
 		return;
 
+	if (!pci_is_pcie(dev))
+		return;
+
 	if (hpp->revision > 1) {
 		dev_warn(&dev->dev, "PCIe settings rev %d not supported\n",
 			 hpp->revision);

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/pci-apply-_hpx-settings-only-to-relevant-devices.patch