From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-pci-owner@vger.kernel.org>
Received: from smtp.codeaurora.org ([198.145.29.96]:46218 "EHLO
        smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1751533AbeEQPCk (ORCPT
        <rfc822;linux-pci@vger.kernel.org>); Thu, 17 May 2018 11:02:40 -0400
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII;
 format=flowed
Date: Thu, 17 May 2018 20:32:39 +0530
From: poza@codeaurora.org
To: Keith Busch <keith.busch@intel.com>
Cc: Linux PCI <linux-pci@vger.kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Sinan Kaya <okaya@codeaurora.org>
Subject: Re: [PATCHv2 7/7] PCI/DPC: Print AER status in DPC event handling
In-Reply-To: <20180402162203.3370-8-keith.busch@intel.com>
References: <20180402162203.3370-1-keith.busch@intel.com>
 <20180402162203.3370-8-keith.busch@intel.com>
Message-ID: <12ab6f9ef1ab79fd09ff7ec583e1d2da@codeaurora.org>
Sender: linux-pci-owner@vger.kernel.org
List-ID: <linux-pci.vger.kernel.org>

On 2018-04-02 21:52, Keith Busch wrote:
> A DPC enabled device suppresses ERR_(NON)FATAL messages, preventing the
> AER handler from reporting error details. If the DPC trigger reason 
> says
> the downstream port detected the error, this patch has the DPC driver
> collect the AER uncorrectable status for logging, then clears the 
> status.
> 
> Signed-off-by: Keith Busch <keith.busch@intel.com>
> ---
>  drivers/pci/pcie/pcie-dpc.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/pcie/pcie-dpc.c b/drivers/pci/pcie/pcie-dpc.c
> index e12837ee4f1c..76f963a5089e 100644
> --- a/drivers/pci/pcie/pcie-dpc.c
> +++ b/drivers/pci/pcie/pcie-dpc.c
> @@ -85,6 +85,7 @@ static void dpc_wait_link_inactive(struct dpc_dev 
> *dpc)
> 
>  static void dpc_work(struct work_struct *work)
>  {
> +	struct aer_err_info info;
>  	struct dpc_dev *dpc = container_of(work, struct dpc_dev, work);
>  	struct pci_dev *dev, *temp, *pdev = dpc->dev->port;
>  	struct pci_bus *parent = pdev->subordinate;
> @@ -108,8 +109,12 @@ static void dpc_work(struct work_struct *work)
>  		 (ext_reason == 1) ? "software trigger" :
>  				     "reserved error");
> 
> -	if (dpc->rp_extensions && reason == 3 && ext_reason == 0)
> +	if (dpc->rp_extensions && reason == 3 && ext_reason == 0) {
>  		pio_status = dpc_process_rp_pio_error(dpc);
> +	} else if (reason == 0 && aer_get_device_error_info(pdev, &info)) {
> +		aer_print_error(pdev, &info);
> +		pci_cleanup_aer_uncorrect_error_status(pdev);
> +	}
> 
>  	pci_lock_rescan_remove();
>  	list_for_each_entry_safe_reverse(dev, temp, &parent->devices,


I am not sure if this series is in pursuit. but was wondering why do we 
need to clear aer status in DPC (when DPC is triggered)?
because

6.2.10 for Downstream Port Containment:

   When DPC is triggered due to receipt of an uncorrectable error 
Message,
   the Requester ID from the Message is recorded in the DPC Error
   Source ID register and that Message is discarded and not forwarded
   Upstream. When DPC is triggered by an unmasked uncorrectable error,
   that error will not be signaled with an uncorrectable error Message,
   even if otherwise enabled.

so when DPC is active, the msg is discarded and not forwarded to 
upstream.
which means that we should find AER status set in RP or Switch.

Regards,
Oza.