From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
Bjorn Helgaas <helgaas@kernel.org>
Cc: "Pali Rohár" <pali@kernel.org>,
vtolkm@gmail.com, linux-pci@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
"Rob Herring" <robh@kernel.org>,
"Ilias Apalodimas" <ilias.apalodimas@linaro.org>,
"Marek Behún" <marek.behun@nic.cz>,
"Jason Cooper" <jason@lakedaemon.net>
Subject: Re: PCI trouble on mvebu (Turris Omnia)
Date: Fri, 30 Oct 2020 00:15:57 +0100 [thread overview]
Message-ID: <877dr8oc7m.fsf@toke.dk> (raw)
In-Reply-To: <20201029225409.2accead3@windsurf.home>
Thomas Petazzoni <thomas.petazzoni@bootlin.com> writes:
> Hello,
>
> On Thu, 29 Oct 2020 14:30:22 -0500
> Bjorn Helgaas <helgaas@kernel.org> wrote:
>
>> We could quirk these NICs to avoid the retrain, but since aardvark and
>> mvebu have no obvious connection and WLE200/WLE900 and MT76 have no
>> obvious connection, I doubt there's a simple hardware defect that
>> explains all these.
>
> aardvark and mvebu have one very strong connection: they are the only
> two drivers making use of the PCI Bridge emulation logic in
> drivers/pci/pci-bridge-emul.c:
>
> drivers/pci$ git grep pci-bridge-emul
> akefile:obj-$(CONFIG_PCI_BRIDGE_EMUL) += pci-bridge-emul.o
> controller/pci-aardvark.c:#include "../pci-bridge-emul.h"
> controller/pci-mvebu.c:#include "../pci-bridge-emul.h"
> pci-bridge-emul.c:#include "pci-bridge-emul.h"
>
> I haven't read the whole thread, but it is important to keep in mind
> that on those two platforms, the PCI Bridge seen by Linux is *not* a
> real HW bridge. It is faked by the the pci-bridge-emul code. So if this
> code has defects/bugs in how it emulates a PCI Bridge behavior, you
> might see weird things.
Ohh, that's interesting. Why does it need to emulate it?
And could this cause things weird interactions like what I'm seeing,
where a somewhat buggy device in slot 2 affects the ability to retrain
the link also in slot 1, but only if there's no device in slot 3?
-Toke
next prev parent reply other threads:[~2020-10-29 23:16 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-27 15:43 PCI trouble on mvebu (Turris Omnia) Toke Høiland-Jørgensen
2020-10-27 17:20 ` Bjorn Helgaas
2020-10-27 17:44 ` ™֟☻̭҇ Ѽ ҉ ®
2020-10-27 18:59 ` Toke Høiland-Jørgensen
2020-10-27 20:20 ` Toke Høiland-Jørgensen
2020-10-27 21:22 ` ™֟☻̭҇ Ѽ ҉ ®
2020-10-27 21:31 ` Toke Høiland-Jørgensen
2020-10-27 22:01 ` ™֟☻̭҇ Ѽ ҉ ®
2020-10-27 22:12 ` Toke Høiland-Jørgensen
2020-10-27 18:56 ` Toke Høiland-Jørgensen
2020-10-28 13:36 ` Toke Høiland-Jørgensen
2020-10-28 14:42 ` Bjorn Helgaas
2020-10-28 15:08 ` Toke Høiland-Jørgensen
2020-10-28 16:40 ` ™֟☻̭҇ Ѽ ҉ ®
2020-10-28 23:16 ` Bjorn Helgaas
2020-10-29 10:09 ` Pali Rohár
2020-10-29 10:56 ` ™֟☻̭҇ Ѽ ҉ ®
2020-10-29 11:12 ` Toke Høiland-Jørgensen
2020-10-29 19:30 ` Bjorn Helgaas
2020-10-29 19:56 ` ™֟☻̭҇ Ѽ ҉ ®
2020-10-29 19:57 ` Andrew Lunn
2020-10-29 21:55 ` Thomas Petazzoni
2020-10-29 20:18 ` Toke Høiland-Jørgensen
2020-10-29 22:09 ` Toke Høiland-Jørgensen
2020-10-29 20:58 ` Marek Behun
2020-10-30 10:08 ` Pali Rohár
2020-10-30 10:45 ` Marek Behun
2020-10-29 21:54 ` Thomas Petazzoni
2020-10-29 23:15 ` Toke Høiland-Jørgensen [this message]
2020-10-30 8:23 ` Thomas Petazzoni
2020-10-30 10:15 ` Pali Rohár
2020-10-29 10:41 ` Toke Høiland-Jørgensen
2020-10-29 11:18 ` ™֟☻̭҇ Ѽ ҉ ®
2020-10-30 11:23 ` Pali Rohár
2020-10-30 13:02 ` Toke Høiland-Jørgensen
2020-10-30 14:23 ` Pali Rohár
2020-10-30 14:54 ` ™֟☻̭҇ Ѽ ҉ ®
2020-10-31 12:49 ` Toke Høiland-Jørgensen
2020-11-02 15:24 ` Pali Rohár
2020-11-02 15:54 ` Toke Høiland-Jørgensen
2020-11-02 16:18 ` ™֟☻̭҇ Ѽ ҉ ®
2020-11-02 16:33 ` Toke Høiland-Jørgensen
2021-03-15 19:58 ` Pali Rohár
2021-03-16 9:25 ` Pali Rohár
2021-03-18 22:43 ` Toke Høiland-Jørgensen
2021-03-18 23:16 ` Pali Rohár
2021-03-26 12:50 ` Pali Rohár
2021-03-26 15:25 ` Toke Høiland-Jørgensen
2021-03-26 15:34 ` Pali Rohár
2021-03-26 16:54 ` Toke Høiland-Jørgensen
2021-03-26 17:11 ` Pali Rohár
2021-03-26 17:51 ` Toke Høiland-Jørgensen
2021-03-29 17:09 ` Pali Rohár
2021-03-31 14:02 ` Toke Høiland-Jørgensen
2021-03-31 16:15 ` Pali Rohár
2021-03-31 16:53 ` Toke Høiland-Jørgensen
2020-10-29 1:21 ` Marek Behun
2020-10-29 15:12 ` Rob Herring
2020-10-27 18:03 ` Marek Behun
2020-10-27 19:00 ` Toke Høiland-Jørgensen
2020-10-27 20:19 ` Marek Behun
2020-10-27 20:49 ` Toke Høiland-Jørgensen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=877dr8oc7m.fsf@toke.dk \
--to=toke@redhat.com \
--cc=helgaas@kernel.org \
--cc=ilias.apalodimas@linaro.org \
--cc=jason@lakedaemon.net \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-pci@vger.kernel.org \
--cc=marek.behun@nic.cz \
--cc=pali@kernel.org \
--cc=robh@kernel.org \
--cc=thomas.petazzoni@bootlin.com \
--cc=vtolkm@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).