linux-kernel - Re: [PATCH v9 7/8] PCI/DPC: Clear AER registers in EDR mode

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Date:   Mon, 28 Oct 2019 18:27:32 -0500
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     sathyanarayanan.kuppuswamy@...ux.intel.com
Cc:     linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        ashok.raj@...el.com, keith.busch@...el.com
Subject: Re: [PATCH v9 7/8] PCI/DPC: Clear AER registers in EDR mode

On Thu, Oct 03, 2019 at 04:39:03PM -0700, sathyanarayanan.kuppuswamy@...ux.intel.com wrote:
> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
> 
> As per PCI firmware specification r3.2 Downstream Port Containment
> Related Enhancements ECN, 

Specific reference, please, e.g., the section/table/figure of the PCI
Firmware Spec being modified by the ECN.

> OS is responsible for clearing the AER
> registers in EDR mode. So clear AER registers in dpc_process_error()
> function.
> 
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
> Acked-by: Keith Busch <keith.busch@...el.com>
> ---
>  drivers/pci/pcie/dpc.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
> index fafc55c00fe0..de2d892bc7c4 100644
> --- a/drivers/pci/pcie/dpc.c
> +++ b/drivers/pci/pcie/dpc.c
> @@ -275,6 +275,10 @@ static void dpc_process_error(struct dpc_dev *dpc)
>  		pci_aer_clear_fatal_status(pdev);
>  	}
>  
> +	/* In EDR mode, OS is responsible for clearing AER registers */
> +	if (dpc->firmware_dpc)

I guess "EDR mode" is effectively the same as "firmware-first mode"?

At least, the only place we set "firmware_dpc = 1" is:

  +       if (pcie_aer_get_firmware_first(pdev))
  +               dpc->firmware_dpc = 1;

If they're the same, why do we need two different names for it?

> +		pci_cleanup_aer_error_status_regs(pdev);
> +
>  	/*
>  	 * Irrespective of whether the DPC event is triggered by
>  	 * ERR_FATAL or ERR_NONFATAL, since the link is already down,
> -- 
> 2.21.0
>