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From: "Kuppuswamy, Sathyanarayanan"  <sathyanarayanan.kuppuswamy@linux.intel.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: bhelgaas@google.com, linux-pci@vger.kernel.org,
	linux-kernel@vger.kernel.org, ashok.raj@intel.com,
	Jay Vosburgh <jay.vosburgh@canonical.com>
Subject: Re: [PATCH v3 1/1] PCI/ERR: Fix reset logic in pcie_do_recovery() call
Date: Tue, 22 Sep 2020 16:44:05 -0700	[thread overview]
Message-ID: <704c39bf-6f0c-bba3-70b8-91de6a445e43@linux.intel.com> (raw)
In-Reply-To: <20200922233333.GA2239404@bjorn-Precision-5520>



On 9/22/20 4:33 PM, Bjorn Helgaas wrote:
> On Tue, Sep 22, 2020 at 02:44:51PM -0700, Kuppuswamy, Sathyanarayanan wrote:
>>
>>
>> On 9/22/20 11:52 AM, Bjorn Helgaas wrote:
>>> On Fri, Jul 24, 2020 at 12:07:55PM -0700, sathyanarayanan.kuppuswamy@linux.intel.com wrote:
>>>> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>>>>
>>>> Current pcie_do_recovery() implementation has following two issues:
>>>>
>>>
>>> I'm having trouble parsing this out, probably just lack of my
>>> understanding...
>>>
>>>> 1. Fatal (DPC) error recovery is currently broken for non-hotplug
>>>> capable devices. Current fatal error recovery implementation relies
>>>> on PCIe hotplug (pciehp) handler for detaching and re-enumerating
>>>> the affected devices/drivers. pciehp handler listens for DLLSC state
>>>> changes and handles device/driver detachment on DLLSC_LINK_DOWN event
>>>> and re-enumeration on DLLSC_LINK_UP event. So when dealing with
>>>> non-hotplug capable devices, recovery code does not restore the state
>>>> of the affected devices correctly.
>>>
>>> Apparently in the hotplug case, something *does* restore the state of
>>> affected devices?
>>
>> Yes, in hotplug case, DLLSC state change handler takes over detachment
>> /cleanup and re-attachment of affected devices/drivers.
> 
> Where does the restore happen here?  I.e., what function does this?

DLLSC link down event will remove affected devices/drivers. And link up event
will re-create all devices.

on DLLSC link down event
->pciehp_ist()
   ->pciehp_handle_presence_or_link_change()
     ->pciehp_disable_slot()
       ->__pciehp_disable_slot()
         ->remove_board()
           ->pciehp_unconfigure_device()

on DLLSC link up event
->pciehp_ist()
   ->pciehp_handle_presence_or_link_change()
     ->pciehp_enable_slot()
       ->__pciehp_enable_slot()
         ->board_added()
           ->pciehp_configure_device()

> 

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer

  reply	other threads:[~2020-09-22 23:44 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <3cad1a07-509b-ef51-f635-71def2ff8293@linux.intel.com>
2020-09-22 23:33 ` [PATCH v3 1/1] PCI/ERR: Fix reset logic in pcie_do_recovery() call Bjorn Helgaas
2020-09-22 23:44   ` Kuppuswamy, Sathyanarayanan [this message]
2020-09-24  1:15     ` Sinan Kaya
2020-09-24  2:04       ` Kuppuswamy, Sathyanarayanan
2020-09-24  2:16         ` Sinan Kaya
2020-09-24  2:51           ` Kuppuswamy, Sathyanarayanan
2020-09-24  3:13             ` Sinan Kaya
2020-09-24  4:06               ` Kuppuswamy, Sathyanarayanan
2020-09-24 20:52                 ` Sinan Kaya
2020-09-25  5:11                   ` Kuppuswamy, Sathyanarayanan
2020-09-25 16:55                     ` Sinan Kaya
2020-09-25 17:11                       ` Kuppuswamy, Sathyanarayanan
2020-09-25 17:47                         ` Sinan Kaya
2020-09-25 18:16                           ` Kuppuswamy, Sathyanarayanan
2020-09-25 18:30                             ` Sinan Kaya
2020-09-28  2:43                               ` Kuppuswamy, Sathyanarayanan
2020-09-28  8:41                                 ` Ethan Zhao
2020-09-28 11:17                                 ` Sinan Kaya
2020-09-28 12:16                                   ` Sinan Kaya
2020-09-28 17:15                                   ` Kuppuswamy, Sathyanarayanan
2020-09-28 18:02                                     ` Sinan Kaya
2020-09-28 18:25                                       ` Sinan Kaya
2020-09-28 18:32                                         ` Kuppuswamy, Sathyanarayanan
2020-10-12  5:13                                           ` Kuppuswamy, Sathyanarayanan
2020-10-12 14:51                                             ` Sinan Kaya
2020-09-28 12:11                                 ` Sinan Kaya
2020-09-25 23:50                             ` Sinan Kaya
2020-07-24 19:07 sathyanarayanan.kuppuswamy
2020-09-01  5:41 ` Kuppuswamy, Sathyanarayanan
2020-09-22 18:52 ` Bjorn Helgaas

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