linux-kernel - Re: [PATCH v3 1/1] PCI/ERR: Fix reset logic in pcie_do

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Message-ID: <20200922233333.GA2239404@bjorn-Precision-5520>
Date:   Tue, 22 Sep 2020 18:33:33 -0500
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     "Kuppuswamy, Sathyanarayanan" 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>
Cc:     bhelgaas@...gle.com, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org, ashok.raj@...el.com,
        Jay Vosburgh <jay.vosburgh@...onical.com>
Subject: Re: [PATCH v3 1/1] PCI/ERR: Fix reset logic in pcie_do_recovery()
 call

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@...ux.intel.com wrote:
> > > From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.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?