Re: [PATCH] ASPM: Fix pcie devices with non-pcie children

From: Colin Ian King
Date: Tue Mar 27 2012 - 12:58:03 EST

On 27/03/12 15:17, Matthew Garrett wrote:
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@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
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 86111d9..41e367b 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -521,9 +521,6 @@ 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
@@ -532,6 +529,16 @@ 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

We got a user who's now verified this fixes the BUG_ON() during boot,

.. so this does the trick. Thanks Matthew.
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