When scanning PCI devices for hot-add, it guarantee function 0 is scanned
at first. And when destroying PCI devices for hot-removal, we also need to
destroy function 0 at last, but currently there's no such guarantees.
On 2012-10-9 15:42, Yijing Wang wrote:
> On 2012/10/9 11:42, Jiang Liu wrote:
>> How about this patch, which disables ARI when adding new PCI devices?
>> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
>> index 5485883..c841aa6 100644
>> --- a/drivers/pci/pci.c
>> +++ b/drivers/pci/pci.c
>> @@ -2016,13 +2016,14 @@ void pci_free_cap_save_buffers(struct pci_dev *dev)
>> void pci_enable_ari(struct pci_dev *dev)
>> {
>
> I think it's ok. Delay to disable ARI until next hot add is safe.
> Maybe rename as pci_configure_ari is better.
>
>> u32 cap;
>> + bool enable = true;
>> struct pci_dev *bridge;
>>
>> if (pcie_ari_disabled || !pci_is_pcie(dev) || dev->devfn)
>> return;
>>
>> if (!pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI))
>> - return;
>> + enable = false;
>>
>> bridge = dev->bus->self;
>> if (!bridge)
>> @@ -2032,8 +2033,15 @@ void pci_enable_ari(struct pci_dev *dev)
>> if (!(cap & PCI_EXP_DEVCAP2_ARI))
>> return;
>>
>> - pcie_capability_set_word(bridge, PCI_EXP_DEVCTL2, PCI_EXP_DEVCTL2_ARI);
>> - bridge->ari_enabled = 1;
>> + if (enable) {
>> + pcie_capability_set_word(bridge, PCI_EXP_DEVCTL2,
>> + PCI_EXP_DEVCTL2_ARI);
>> + bridge->ari_enabled = 1;
>> + } else {
>> + pcie_capability_clear_word(bridge, PCI_EXP_DEVCTL2,
>> + PCI_EXP_DEVCTL2_ARI);
>> + bridge->ari_enabled = 0;
>> + }
>> }
>>
>> /**
>>
>> On 2012-10-9 11:03, Yijing Wang wrote:
>>> pci_enable_ari will be called if an ARI pci device found, then set its bridge ARI Forwarding Enable
>>> bit in Device Control 2 Register. But the bridge ARI Forwarding Enable bit will never be cleared
>>> when an ARI device hot removed.
>>>
>>> my steps:
>>> 1. Hot add an ARI pci device;
>>> 2. Hot remove the ARI pci device;
>>> 3. Hot add an non ARI pci device;
>>>
>>> In this case, after setp 3, we could only find fun 0 of non ARI pci device because of its bridge ARI Forwarding Enable
>>> bit set.
>>>
>>> As PCIe Spec 2.0(6.13/441) recommends:
>>> "Following a hot-plug event below a Downstream Port, it is strongly recommended that software
>>> Clear the ARI Forwarding Enable bit in the Downstream Port until software determines that a
>>> newly added component is in fact an ARI Device"
>>>
>>> This series of patches fix this problem.
>>>
>>> Yijing Wang (7):
>>> PCI: rework pci_enable_ari for support disable ari forwarding
>>> PCI, acpiphp: disable ARI forwarding for acpiphp
>>> PCI, pciehp: disable ARI forwarding for pciehp
>>> PCI, cpqphp: disable ARI forwarding for cpqphp
>>> PCI, shpchp: disable ARI forwarding for shpchp
>>> PCI, sgi: disable ARI forwarding for sgiphp
>>> PCI, ibmphp: disable ARI forwarding for ibmphp
>>>
>>> drivers/pci/hotplug/acpiphp_glue.c | 1 +
>>> drivers/pci/hotplug/cpci_hotplug_pci.c | 1 +
>>> drivers/pci/hotplug/cpqphp_pci.c | 1 +
>>> drivers/pci/hotplug/ibmphp_core.c | 1 +
>>> drivers/pci/hotplug/pciehp_pci.c | 1 +
>>> drivers/pci/hotplug/sgi_hotplug.c | 1 +
>>> drivers/pci/hotplug/shpchp_pci.c | 1 +
>>> drivers/pci/pci.c | 16 +++++++++++-----
>>> drivers/pci/pci.h | 2 +-
>>> drivers/pci/probe.c | 2 +-
>>> 10 files changed, 20 insertions(+), 7 deletions(-)
>>>
>>>
>>>
>>> .
>>>
>>
>>
>>
>> .
>>
>
>
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