linux-kernel - Re: [RESEND PATCH v8 06/10] serial: sc16is7xx: fix regression with GPIO configuration

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230731124600.39eb8d5c132f9338c2897543@hugovil.com>
Date:   Mon, 31 Jul 2023 12:46:00 -0400
From:   Hugo Villeneuve <hugo@...ovil.com>
To:     Rob Herring <robh+dt@...nel.org>
Cc:     Greg KH <gregkh@...uxfoundation.org>,
        krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
        jirislaby@...nel.org, jringle@...dpoint.com,
        isaac.true@...onical.com, jesse.sung@...onical.com,
        tomasz.mon@...lingroup.com, l.perczak@...lintechnologies.com,
        linux-serial@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org,
        Hugo Villeneuve <hvilleneuve@...onoff.com>,
        stable@...r.kernel.org,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Lech Perczak <lech.perczak@...lingroup.com>
Subject: Re: [RESEND PATCH v8 06/10] serial: sc16is7xx: fix regression with
 GPIO configuration

On Mon, 31 Jul 2023 09:31:53 -0600
Rob Herring <robh+dt@...nel.org> wrote:

> On Mon, Jul 24, 2023 at 9:54 AM Hugo Villeneuve <hugo@...ovil.com> wrote:
> >
> > On Sat, 22 Jul 2023 17:15:26 +0200
> > Greg KH <gregkh@...uxfoundation.org> wrote:
> >
> > > On Sat, Jul 22, 2023 at 10:47:24AM -0400, Hugo Villeneuve wrote:
> > > > On Fri, 21 Jul 2023 13:24:19 -0600
> > > > Rob Herring <robh+dt@...nel.org> wrote:
> > > >
> > > > > On Fri, Jul 21, 2023 at 10:19 AM Hugo Villeneuve <hugo@...ovil.com> wrote:
> > > > > >
> > > > > > From: Hugo Villeneuve <hvilleneuve@...onoff.com>
> > > > > >
> > > > > > Commit 679875d1d880 ("sc16is7xx: Separate GPIOs from modem control lines")
> > > > > > and commit 21144bab4f11 ("sc16is7xx: Handle modem status lines")
> > > > > > changed the function of the GPIOs pins to act as modem control
> > > > > > lines without any possibility of selecting GPIO function.
> > > > >
> > > > > Requiring a new DT property is not fixing a kernel regression. You
> > > > > should be returning the kernel to original behavior and then have a
> > > > > new DT property for new behavior.
> > > >
> > > > Hi Rob,
> > > > please read the entire patch history starting from V1
> > > >  and you will understand why this course of action was
> > > >  not selected.
> > >
> > > That's not going to happen, sorry, you need to explain it here, in this
> > > patch series, why a specific action is being taken over another one, as
> > > no one has time to go dig through past history, sorry.
> >
> > Hi Rob,
> > I initially submitted a patch to revert the kernel to original
> > behavior, but it created more problems because the patch was
> > unfortunately split in two separate patches, and mixed with other non
> > closely-related changes. It was also noted to me that reverting to the
> > old behavior would break things for some users.
> >
> > It was suggested to me by a more experienced kernel developer to
> > "suggest a fix, instead of hurrying a revert":
> >
> >     https://lkml.org/lkml/2023/5/17/758
> 
> Do I have to go read this to decipher the justification and reasoning?
> When Greg says "in this patch series", he means in the commit messages
> of the patches. You send v9 already and it doesn't have that. The
> patchset needs to stand on its own summarizing any relevant prior
> discussions.
> 
> I never suggested doing a revert.

Hi Rob,
I am sorry, but this is exactly what I "deciphered" from your
original email.

I am trying very hard to understand exactly what you mean, but it is
not that obvious for me. If something is not clear in my commit message,
I will try to improve it. But before, let's try to focus on making sure
I understand more clearly what you want exactly.

> Obviously, someone still wants the
> new feature.

I assume that you refer to the "new feature" as what was added in
the commit 679875d1d880 ("sc16is7xx: Separate GPIOs from modem control
lines")?

Because I did not add a "new feature" myself, I simply restored (or
want to restore) what was working before commit 679875d1d880
(restore GPIO pins as GPIO functions).

I will wait for your clarification on this, and answer your other
comments after.

Hugo.


> The issue is a new feature was added to the kernel, but
> you are requiring a DT change to platforms NOT using the feature.
> Make
> the platforms wanting the new feature to need a DT change. That's
> still not great, but it's much better to affect new platforms rather
> than old, stable platforms. The period of time that regresses is much
> smaller (a few kernel releases vs. years potentially). Of course, if
> it's just those 3 platforms and their maintainers are fine with
> needing this DT change, then that works too. But there's no evidence
> here that they are okay with it. You didn't even do the update of the
> dts files and just left them broken.