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From: Bjorn Helgaas <helgaas@kernel.org>
To: sathyanarayanan.kuppuswamy@linux.intel.com
Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	ashok.raj@intel.com, "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Len Brown <lenb@kernel.org>, Keith Busch <keith.busch@intel.com>,
	Huong Nguyen <huong.nguyen@dell.com>,
	Austin Bolen <Austin.Bolen@dell.com>
Subject: Re: [PATCH v12 8/8] PCI/ACPI: Enable EDR support
Date: Fri, 17 Jan 2020 14:41:15 -0600	[thread overview]
Message-ID: <20200117204115.GA126492@google.com> (raw)
In-Reply-To: <a15c5467ab8d52ede096b598e14c1beae1ce8e48.1578682741.git.sathyanarayanan.kuppuswamy@linux.intel.com>

On Sun, Jan 12, 2020 at 02:44:02PM -0800, sathyanarayanan.kuppuswamy@linux.intel.com wrote:
> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> 
> As per PCI firmware specification r3.2 Downstream Port Containment
> Related Enhancements ECN, sec 4.5.1, OS must implement following steps
> to enable/use EDR feature.
> 
> 1. OS can use bit 7 of _OSC Control Field to negotiate control over
> Downstream Port Containment (DPC) configuration of PCIe port. After _OSC
> negotiation, firmware will Set this bit to grant OS control over PCIe
> DPC configuration and Clear it if this feature was requested and denied,
> or was not requested.
> 
> 2. Also, if OS supports EDR, it should expose its support to BIOS by
> setting bit 7 of _OSC Support Field. And if OS sets bit 7 of _OSC
> Control Field it must also expose support for EDR by setting bit 7 of
> _OSC Support Field.

> --- a/drivers/pci/pcie/portdrv_core.c
> +++ b/drivers/pci/pcie/portdrv_core.c
> @@ -253,10 +253,13 @@ static int get_port_device_capability(struct pci_dev *dev)
>  	/*
>  	 * With dpc-native, allow Linux to use DPC even if it doesn't have
>  	 * permission to use AER.
> +	 * If EDR support is enabled in OS, then even if AER is not handled in
> +	 * OS, DPC service can be enabled.

Can you clarify this comment?  It talks about AER, but the code you
added:

  (IS_ENABLED(CONFIG_PCIE_EDR) && !host->native_dpc)

doesn't have anything to do with AER.

>  	 */
>  	if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
> -	    pci_aer_available() &&
> -	    (pcie_ports_dpc_native || (services & PCIE_PORT_SERVICE_AER)))
> +	    ((IS_ENABLED(CONFIG_PCIE_EDR) && !host->native_dpc) ||
> +	    (pci_aer_available() &&
> +	    (pcie_ports_dpc_native || (services & PCIE_PORT_SERVICE_AER)))))
>  		services |= PCIE_PORT_SERVICE_DPC;

  parent reply	other threads:[~2020-01-17 20:41 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-12 22:43 [PATCH v12 0/8] Add Error Disconnect Recover (EDR) support sathyanarayanan.kuppuswamy
2020-01-12 22:43 ` [PATCH v12 1/8] PCI/ERR: Update error status after reset_link() sathyanarayanan.kuppuswamy
2020-01-12 22:43 ` [PATCH v12 2/8] PCI/DPC: Allow dpc_probe() even if firmware first mode is enabled sathyanarayanan.kuppuswamy
2020-01-12 22:43 ` [PATCH v12 3/8] PCI/DPC: Add dpc_process_error() wrapper function sathyanarayanan.kuppuswamy
2020-01-12 22:43 ` [PATCH v12 4/8] PCI/DPC: Add Error Disconnect Recover (EDR) support sathyanarayanan.kuppuswamy
2020-01-17 22:56   ` Bjorn Helgaas
2020-01-12 22:43 ` [PATCH v12 5/8] PCI/AER: Allow clearing Error Status Register in FF mode sathyanarayanan.kuppuswamy
2020-01-17 22:56   ` Bjorn Helgaas
2020-01-12 22:44 ` [PATCH v12 6/8] PCI/DPC: Update comments related to DPC recovery on NON_FATAL errors sathyanarayanan.kuppuswamy
2020-01-12 22:44 ` [PATCH v12 7/8] PCI/DPC: Clear AER registers in EDR mode sathyanarayanan.kuppuswamy
2020-01-12 22:44 ` [PATCH v12 8/8] PCI/ACPI: Enable EDR support sathyanarayanan.kuppuswamy
2020-01-16 22:10   ` Bjorn Helgaas
2020-01-16 22:24     ` Kuppuswamy Sathyanarayanan
2020-01-16 22:58       ` Bjorn Helgaas
2020-01-16 23:01         ` Kuppuswamy Sathyanarayanan
2020-01-17 20:41   ` Bjorn Helgaas [this message]
2020-01-17 23:04     ` Kuppuswamy Sathyanarayanan
2020-01-14 19:48 ` [PATCH v12 0/8] Add Error Disconnect Recover (EDR) support Bjorn Helgaas
2020-01-18  0:18 ` Bjorn Helgaas
2020-01-18  1:10   ` Kuppuswamy Sathyanarayanan
2020-01-18 15:15     ` Bjorn Helgaas

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