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SubjectRe: [PATCH 1/2] PCI: ASPM exit link state code could skip devices
On Fri, Feb 1, 2013 at 12:55 PM, Joe Lawrence <Joe.Lawrence@stratus.com> wrote:
> On Thu, 31 Jan 2013, Myron Stowe wrote:

>> PCI: ASPM exit link state code is skipping devices
>>
>> From: Myron Stowe <myron.stowe@redhat.com>
>>
>> On PCI bus hotplug removal, 'pcie_aspm_exit_link_state' can potentially
>> skip parent devices that have link_state allocated. Instead of exiting
>> early if a given device in not PCIe, check whether or not the device's
>> parent has link_state allocated. This enables 'pcie_aspm_exit_link_state'
>> to properly clean up parent link_state when the last function in a slot
>> might not be PCIe.
>>
>> Reported-by: Joe Lawrence <joe.lawrence@stratus.com>
>> Signed-off-by: Myron Stowe <myron.stowe@redhat.com>
>> ---
>>
>> drivers/pci/pcie/aspm.c | 5 +----
>> 1 files changed, 1 insertions(+), 4 deletions(-)
>>
>>
>> diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
>> index 8474b6a..aa52727 100644
>> --- a/drivers/pci/pcie/aspm.c
>> +++ b/drivers/pci/pcie/aspm.c
>> @@ -634,10 +634,7 @@ void pcie_aspm_exit_link_state(struct pci_dev *pdev)
>> struct pci_dev *parent = pdev->bus->self;
>> struct pcie_link_state *link, *root, *parent_link;
>>
>> - if (!pci_is_pcie(pdev) || !parent || !parent->link_state)
>> - return;
>> - if ((pci_pcie_type(parent) != PCI_EXP_TYPE_ROOT_PORT) &&
>> - (pci_pcie_type(parent) != PCI_EXP_TYPE_DOWNSTREAM))
>> + if (!parent || !parent->link_state)
>> return;
>>
>> down_read(&pci_bus_sem);
>>
>>
>>
>
> Hi Myron,
>
> The patch tests eliminates the reported crash when hotplugging our
> problem PCI bus.
>
> The additional checks removed from pcie_aspm_exit_link_state (ie, the
> simplification) do appear to be unnecessary as pcie_aspm_init_link_state
> is already preventing such devices from allocating link state.

I added a Tested-by for you, Joe, and applied this to my pci/joe-aspm
branch for v3.9. Thanks!


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