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References: <20230315010732.633992-1-saravanak@google.com> <ZBR1WHPpcrOMFwVe@kroah.com>
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From:   Doug Anderson <dianders@chromium.org>
Date:   Fri, 17 Mar 2023 09:57:19 -0700
Message-ID: <CAD=FV=XUe194BqM42QhZzxQ1M1uDmVbeya34p7shEGjTr2C1SQ@mail.gmail.com>
Subject: Re: [PATCH v2] driver core: Add CONFIG_FW_DEVLINK_SYNC_STATE_TIMEOUT
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Saravana Kannan <saravanak@google.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>, kernel-team@android.com,
        linux-kernel@vger.kernel.org
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Hi,

On Fri, Mar 17, 2023 at 7:12=E2=80=AFAM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Tue, Mar 14, 2023 at 06:07:31PM -0700, Saravana Kannan wrote:
> > Add a build time equivalent of fw_devlink.sync_state=3Dtimeout so that
> > board specific kernels could enable it and not have to deal with settin=
g
> > or cluttering the kernel commandline.
> >
> > Cc: Doug Anderson <dianders@chromium.org>
> > Signed-off-by: Saravana Kannan <saravanak@google.com>
> > ---
> >  drivers/base/Kconfig | 12 ++++++++++++
> >  drivers/base/core.c  |  5 +++++
> >  2 files changed, 17 insertions(+)
> >
> > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
> > index 6f04b831a5c0..aac247512d69 100644
> > --- a/drivers/base/Kconfig
> > +++ b/drivers/base/Kconfig
> > @@ -230,4 +230,16 @@ config GENERIC_ARCH_NUMA
> >         Enable support for generic NUMA implementation. Currently, RISC=
-V
> >         and ARM64 use it.
> >
> > +config FW_DEVLINK_SYNC_STATE_TIMEOUT
> > +     bool
> > +     help
> > +       This is build time equivalent of adding kernel command line par=
ameter
> > +       "fw_devlink.sync_state=3Dtimeout". Give up waiting on consumers=
 and
> > +       call sync_state() on any devices that haven't yet received thei=
r
> > +       sync_state() calls after deferred_probe_timeout has expired or =
by
> > +       late_initcall() if !CONFIG_MODULES. You should almost always wa=
nt to
> > +       select N here unless you have already successfully tested with =
the
> > +       command line option on every system/board your kernel is expect=
ed to
> > +       work on.
>
> As nothing can actually select this, it doesn't make sense to add this
> now, right?  We need a user, otherwise the automated tools will come
> along and remove this option when they figure out that it can't be ever
> used.

I think the hope was that it could be setup as a config that would
show up as user selectable (like in menuconfig). Saravana: the problem
is your bare "bool" above. That should be changed to a description
shown to the user. Like maybe you'd want to change that to:

  bool "sync_state behavior defaults to timeout instead of strict"

-Doug