linux-kernel - Re: [PATCH 0/2] PCI/AER: Consistently use

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Date:   Mon, 19 Nov 2018 10:41:27 -0700
From:   Keith Busch <keith.busch@...el.com>
To:     Sinan Kaya <okaya@...nel.org>
Cc:     Tyler Baicar <baicar.tyler@...il.com>, mr.nuke.me@...il.com,
        helgaas@...gle.com, austin_bolen@...l.com,
        alex_gagniuc@...lteam.com, Shyam_Iyer@...l.com, lukas@...ner.de,
        bhelgaas@...gle.com, rjw@...ysocki.net, lenb@...nel.org,
        ruscur@...sell.cc, sbobroff@...ux.ibm.com, oohall@...il.com,
        linux-pci@...r.kernel.org, linux-acpi@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH 0/2] PCI/AER: Consistently use _OSC to determine who owns
 AER

On Mon, Nov 19, 2018 at 12:42:25PM -0500, Sinan Kaya wrote:
> On 11/19/2018 12:32 PM, Sinan Kaya wrote:
> > > 
> > > But we're not using HEST as a fine grain control. We disable native AER
> > > handling if *any* device has FF set in HEST, and that just forces people
> > > to use pcie_ports=native to get around that.
> > > 
> > 
> > I don't see *any* in the code.  aer_hest_parse() does the HEST table parsing.
> > It switches to firmware first mode if global flag in HEST is set. Otherwise
> > for each BDF in device, hest_match_pci() is used to do a cross-matching against
> > HEST table contents.
> > 
> > Am I missing something?
> 
> I see. I think you are talking about aer_firmware_first, right?
> 
> aer_set_firmware_first() and  pcie_aer_get_firmware_first() seem to do the right
> thing.

Right, but what difference does it make if device specific AER checks do
the right thing if pcie_aer_init() doesn't even register it's port driver?
 
> aer_firmware_first is probably getting set because events are all routed to a
> single root port and aer_acpi_firmware_first() is used to decide whether AER
> should be initialized or not.
> 
> I think I understand what is going on now.
> 
> Still, breaking existing systems that rely on HEST table is not cool.
> I'd rather have users specify "pcie_ports=native" to skip FF rather than
> having broken systems by default to be honest.

The pcie_ports=native work-around ignores FF to potentially unknown
results, though.