[Precise PATCH] (pre-stable) ASPM: Fix pcie devices with non-pcie children

[Tim Gardner]

From: Matthew Garrett <mjg at redhat.com>

BugLink: http://bugs.launchpad.net/bugs/961482

Commit 4949be16822e92a18ea0cc1616319926628092ee changed the behaviour of
pcie_aspm_sanity_check() to always return 0 if aspm is disabled, in order
to avoid cases where we changed ASPM state on pre-PCIe 1.1 devices. This
skipped the secondary function of pcie_aspm_sanity_check which was to avoid
us enabling ASPM on devices that had non-PCIe children, causing us to hit
a BUG_ON later on. Move the aspm_disabled check so we continue to honour
that scenario.

Signed-off-by: Matthew Garrett <mjg at redhat.com>
Cc: stable at vger.kernel.org
Signed-off-by: Colin King <colin.king at canonical.com>
Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
---
 drivers/pci/pcie/aspm.c |   13 ++++++++++---
 1 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 24f049e..2275162 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -500,9 +500,6 @@ static int pcie_aspm_sanity_check(struct pci_dev *pdev)
 	int pos;
 	u32 reg32;
 
-	if (aspm_disabled)
-		return 0;
-
 	/*
 	 * Some functions in a slot might not all be PCIe functions,
 	 * very strange. Disable ASPM for the whole slot
@@ -511,6 +508,16 @@ static int pcie_aspm_sanity_check(struct pci_dev *pdev)
 		pos = pci_pcie_cap(child);
 		if (!pos)
 			return -EINVAL;
+
+		/*
+		 * If ASPM is disabled then we're not going to change
+		 * the BIOS state. It's safe to continue even if it's a
+		 * pre-1.1 device
+		 */
+
+		if (aspm_disabled)
+			continue;
+
 		/*
 		 * Disable ASPM for pre-1.1 PCIe device, we follow MS to use
 		 * RBER bit to determine if a function is 1.1 version device
-- 
1.7.9.1