On 2014/1/30 6:38, Bjorn Helgaas wrote:
> On Mon, Jan 13, 2014 at 04:02:48PM +0800, Yijing Wang wrote:
>> If we found device already exists during hot add device, we should
>> leave it, not to set slot off.
>
> Does this fix a defect? What's the scenario where this fixes a problem
> in the current code? I think this change makes sense, but I'd like to
> have a better description of the problem that we're fixing.
>
> I see the following path that looks like it might be a problem with the
> current code if slot power is off when we resume after a suspend:
>
> pciehp_resume
> pciehp_enable_slot
> board_added
> pciehp_configure_device
>
> Is this the scenario you're addressing?
Yes, it is.
I found this case by reviewing the code. But I have no platform
supports pciehp resume. So I can not test it in real.
Thanks!
Yijing.
>
>> Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
>> ---
>> drivers/pci/hotplug/pciehp_ctrl.c | 3 ++-
>> drivers/pci/hotplug/pciehp_pci.c | 2 +-
>> 2 files changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
>> index 38f0186..f27b0ff 100644
>> --- a/drivers/pci/hotplug/pciehp_ctrl.c
>> +++ b/drivers/pci/hotplug/pciehp_ctrl.c
>> @@ -224,7 +224,8 @@ static int board_added(struct slot *p_slot)
>> if (retval) {
>> ctrl_err(ctrl, "Cannot add device at %04x:%02x:00\n",
>> pci_domain_nr(parent), parent->number);
>> - goto err_exit;
>> + if (retval != -EEXIST)
>> + goto err_exit;
>> }
>>
>> if (PWR_LED(ctrl))
>> diff --git a/drivers/pci/hotplug/pciehp_pci.c b/drivers/pci/hotplug/pciehp_pci.c
>> index aac7a40..9b87b49 100644
>> --- a/drivers/pci/hotplug/pciehp_pci.c
>> +++ b/drivers/pci/hotplug/pciehp_pci.c
>> @@ -48,7 +48,7 @@ int pciehp_configure_device(struct slot *p_slot)
>> "at %04x:%02x:00, cannot hot-add\n", pci_name(dev),
>> pci_domain_nr(parent), parent->number);
>> pci_dev_put(dev);
>> - return -EINVAL;
>> + return -EEXIST;
>> }
>>
>> num = pci_scan_slot(parent, PCI_DEVFN(0, 0));
>> --
>> 1.7.1
>>
>>
>> --
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>
>
--
Thanks!
Yijing
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