[PATCH 3.19.y-ckt 69/99] PCI: Disable all BAR sizing for devices with non-compliant BARs

Kamal Mostafa kamal at canonical.com
Thu Jul 7 18:38:08 UTC 2016

3.19.8-ckt23 -stable review patch.  If anyone has any objections, please let me know.


From: Prarit Bhargava <prarit at redhat.com>

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 3efefa2..b1cbe3d 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -175,9 +175,6 @@ 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! */
@@ -318,6 +315,9 @@ 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);

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