Re: [PATCH 2/6] PCI/DPC: Leave interrupts enabled while handling event

[poza@codeaurora.org]

On 2018-01-30 11:59, Oza Pawandeep wrote:
> + Oza
> 
> On Tue, Jan 30, 2018 at 7:41 AM, Sinan Kaya <okaya@codeaurora.org> 
> wrote:
>> On 1/29/2018 4:31 PM, Keith Busch wrote:
>>> +     if (!work_busy(&dpc->work))
>>> +             schedule_work(&dpc->work);
>> 
>> Isn't there a race condition between the time that dpc_work() clears 
>> PCI_EXP_DPC_STATUS
>> register and when work actually completes by returning from 
>> dpc_work()?
>> 
>> If the interrupt arrives just in this window, this code will not 
>> schedule the work.
>> 
>> --
>> Sinan Kaya
>> Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm 
>> Technologies, Inc.
>> Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a 
>> Linux Foundation Collaborative Project.

besides, there is one more problem which I was debugging:
if RP doesnt support MSI, then legacy interrupts are not well handled 
and we get interrupt storm.
this is because;
PCI_EXP_DPC_STATUS_INTERRUPT is being cleared in deferred work.
which should get cleared in dpc_irq interrupt handler.
I will post a patch for this, but I see there are lot of changes being 
made in dpc and aer lately.

Bjorn: Can you please help to review my AER/DPC series of patches so 
that I do not have to keep rebasing and do manual merge ?

Regards,
Oza.