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Message-ID: <2d4e8811-dce6-c891-e92d-e3746434685e@linux.intel.com>
Date:   Tue, 15 Mar 2022 10:26:46 -0700
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Subject: Re: [PATCH v2] PCI/AER: Handle Multi UnCorrectable/Correctable errors
 properly
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To:     Eric Badger <ebadger@purestorage.com>
Cc:     Bjorn Helgaas <bhelgaas@google.com>,
        Russell Currey <ruscur@russell.cc>,
        Oliver OHalloran <oohall@gmail.com>, linux-pci@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
References: <20220315050842.120063-1-sathyanarayanan.kuppuswamy@linux.intel.com>
 <20220315171425.GA1521135@ebps>
From:   Sathyanarayanan Kuppuswamy 
        <sathyanarayanan.kuppuswamy@linux.intel.com>
In-Reply-To: <20220315171425.GA1521135@ebps>
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On 3/15/22 10:14 AM, Eric Badger wrote:
>>   # Prep injection data for a correctable error.
>>   $ cd /sys/kernel/debug/apei/einj
>>   $ echo 0x00000040 > error_type
>>   $ echo 0x4 > flags
>>   $ echo 0x891000 > param4
>>
>>   # Root Error Status is initially clear
>>   $ setpci -s <Dev ID> ECAP0001+0x30.w
>>   0000
>>
>>   # Inject one error
>>   $ echo 1 > error_inject
>>
>>   # Interrupt received
>>   pcieport <Dev ID>: AER: Root Error Status 0001
>>
>>   # Inject another error (within 5 seconds)
>>   $ echo 1 > error_inject
>>
>>   # No interrupt received, but "multiple ERR_COR" is now set
>>   $ setpci -s <Dev ID> ECAP0001+0x30.w
>>   0003
>>
>>   # Wait for a while, then clear ERR_COR. A new interrupt immediately
>>     fires.
>>   $ setpci -s <Dev ID> ECAP0001+0x30.w=0x1
>>   pcieport <Dev ID>: AER: Root Error Status 0002
>>
>> Currently, the above issue has been only reproduced in the ICL server
>> platform.
>>
>> [Eric: proposed reproducing steps]
> Hmm, this differs from the procedure I described on v1, and I don't
> think will work as described here.

I have attempted to modify the steps to reproduce it without returning
IRQ_NONE for all cases (which will break the functionality). But I
think I did not correct the last few steps.

How about replacing the last 3 steps with following?

  # Inject another error (within 5 seconds)
  $ echo 1 > error_inject

  # You will get a new IRQ with only multiple ERR_COR bit set
  pcieport <Dev ID>: AER: Root Error Status 0002

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer