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SubjectRe: [PATCH V5 3/3] PCI: Mask and unmask hotplug interrupts during reset
On 2018-07-03 19:29, Lukas Wunner wrote:
> On Tue, Jul 03, 2018 at 09:31:24AM -0400, Sinan Kaya wrote:
>> Issue is observing hotplug link down event in the middle of AER
>> recovery
>> as in my previous reply.
>>
>> If we mask hotplug interrupts before secondary bus reset via my patch,
>> then hotplug driver will not observe both link up and link down
>> interrupts.
>>
>> If we don't mask hotplug interrupts, we have a race condition.
>
> I assume that a bus reset not only causes a link and presence event but
> also clears the Presence Detect State bit in the Slot Status register
> and the Data Link Layer Link Active bit in the Link Status register
> momentarily.
>
> pciehp may access those two bits concurrently to the AER driver
> performing a slot reset. So it may not be sufficient to mask
> the interrupt.

Was just wondering that you are protecting Presence Detect State bit
with reset_lock, mainly in pciehp_ist
but with hotplug interrupt disabled, is there another way that it
hotplug code gets activated ?

>
> I've posted this patch to address the issue:
> https://patchwork.ozlabs.org/patch/930391/
>
> Thanks,
>
> Lukas

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