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(-)
>>
>>
>>
>> .
>>
>
>
>
> .
>
--
Thanks!
Yijing
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