Re: [PATCH 1/5] PCI/AER: Allow drivers to opt in to Bus Reset on Non-Fatal Errors

[Lukas Wunner <lukas@wunner.de>]

On Wed, Aug 13, 2025 at 04:01:09PM -0700, Sathyanarayanan Kuppuswamy wrote:
> On 8/12/25 10:11 PM, Lukas Wunner wrote:
> > The file Documentation/PCI/pcieaer-howto.rst hints at a rationale for
> > always performing a Bus Reset on Fatal Errors:  "Fatal errors [...] cause
> > the link to be unreliable.  [...] This [reset_link] callback is used to
> > reset the PCIe physical link when a fatal error happens.  If an error
> > message indicates a fatal error, [...] performing link reset at upstream
> > is necessary."
> 
> In the code we don't seem to differentiate link_reset and slot_reset. But
> the Documentation calls them into two steps. Do you think we should
> fix the Documentation?

reset_link and slot_reset are two different things:

* slot_reset is the ->slot_reset() callback in struct pci_error_handlers.

* reset_link is the reset_subordinates() callback passed in to
  pcie_do_recovery().

Commit 8f1bbfbc3596 renamed reset_link() to reset_subordinates() but
neglected to update Documentation/PCI/pcieaer-howto.rst.

Commit b6cf1a42f916 dropped the reset_link() callback from struct
pcie_port_service_driver and dropped default_reset_link() in favor
of passing aer_root_reset() to pcie_do_recovery().  Yet the documentation
continues referring to a "default reset_link callback" and incorrectly
claims that "Upstream Port drivers may provide their own reset_link
functions".

I've begun updating the documentation and intend to submit that separately.

Thanks,

Lukas