Re: [PATCH V5 3/3] PCI: Mask and unmask hotplug interrupts during reset

[poza@codeaurora.org]

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