linux-kernel - Re: [PATCH] Documentation: PCI: pci-error-recovery: rearrange the general sequence

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Message-ID: <20210629033437.GB1492@buildhost>
Date:   Tue, 29 Jun 2021 11:34:37 +0800
From:   Wesley Sheng <wesley.sheng@....com>
To:     Oliver O'Halloran <oohall@...il.com>, linasvepstas@...il.com,
        ruscur@...sell.cc, bhelgaas@...gle.com, corbet@....net,
        linux-pci@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     wesleyshenggit@...a.com, wesley.sheng@....com
Subject: Re: [PATCH] Documentation: PCI: pci-error-recovery: rearrange the
 general sequence

On Fri, Jun 18, 2021 at 05:21:32PM +1000, Oliver O'Halloran wrote:
> On Fri, Jun 18, 2021 at 4:05 PM Wesley Sheng <wesley.sheng@....com> wrote:
> >
> > Reset_link() callback function was called before mmio_enabled() in
> > pcie_do_recovery() function actually, so rearrange the general
> > sequence betwen step 2 and step 3 accordingly.
> 
> I don't think this is true in all cases. If pcie_do_recovery() is
> called with state==pci_channel_io_normal (i.e. non-fatal AER) the link
> won't be reset. EEH (ppc PCI error recovery thing) also uses
> .mmio_enabled() as described.

Yes, in case of non-fatal AER, reset_link() callback (aer_root_reset() for 
AER and dpc_reset_link() for DPC) will not be invoked. And if 
.error_detected() return PCI_ERS_RESULT_CAN_RECOVER, .mmio_enabled() be
called followed.

But if pcie_do_recovery() is called with state == pci_channel_io_frozen,
reset_link() callback is called after .error_detected() but before
.mmio_enabled(). So I thought Step 2: MMIO Enabled and Step 3: Link Reset
should rearrange their sequence.