[4.2.y-ckt stable] Patch "PCI: Disable all BAR sizing for devices with non-compliant BARs" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    PCI: Disable all BAR sizing for devices with non-compliant BARs

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    https://git.launchpad.net/~canonical-kernel/linux/+git/linux-stable-ckt/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt12.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From f4ef0f9b39f4962a262bb894ef2c13de9e5dcea1 Mon Sep 17 00:00:00 2001
From: Prarit Bhargava <prarit at redhat.com>
Date: Wed, 11 May 2016 12:27:16 -0400
Subject: PCI: Disable all BAR sizing for devices with non-compliant BARs

commit ad67b437f187ea818b2860524d10f878fadfdd99 upstream.

b84106b4e229 ("PCI: Disable IO/MEM decoding for devices with non-compliant
BARs") disabled BAR sizing for BARs 0-5 of devices that don't comply with
the PCI spec.  But it didn't do anything for expansion ROM BARs, so we
still try to size them, resulting in warnings like this on Broadwell-EP:

  pci 0000:ff:12.0: BAR 6: failed to assign [mem size 0x00000001 pref]

Move the non-compliant BAR check from __pci_read_base() up to
pci_read_bases() so it applies to the expansion ROM BAR as well as
to BARs 0-5.

Note that direct callers of __pci_read_base(), like sriov_init(), will now
bypass this check.  We haven't had reports of devices with broken SR-IOV
BARs yet.

[bhelgaas: changelog]
Fixes: b84106b4e229 ("PCI: Disable IO/MEM decoding for devices with non-compliant BARs")
Signed-off-by: Prarit Bhargava <prarit at redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
CC: Thomas Gleixner <tglx at linutronix.de>
CC: Ingo Molnar <mingo at redhat.com>
CC: "H. Peter Anvin" <hpa at zytor.com>
CC: Andi Kleen <ak at linux.intel.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/pci/probe.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 8cb5197..ea55f82 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -176,9 +176,6 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
 	u16 orig_cmd;
 	struct pci_bus_region region, inverted_region;

-	if (dev->non_compliant_bars)
-		return 0;
-
 	mask = type ? PCI_ROM_ADDRESS_MASK : ~0;

 	/* No printks while decoding is disabled! */
@@ -319,6 +316,9 @@ static void pci_read_bases(struct pci_dev *dev, unsigned int howmany, int rom)
 {
 	unsigned int pos, reg;

+	if (dev->non_compliant_bars)
+		return;
+
 	for (pos = 0; pos < howmany; pos++) {
 		struct resource *res = &dev->resource[pos];
 		reg = PCI_BASE_ADDRESS_0 + (pos << 2);
--
2.7.4