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From:   Saravana Kannan <saravanak@google.com>
Date:   Wed, 13 Jan 2021 13:27:27 -0800
Message-ID: <CAGETcx_2vOrMy-kdbHkK0UiybYda83bVSznNTuAECmKXHhKOSw@mail.gmail.com>
Subject: Re: [PATCH v1 0/5] Enable fw_devlink=on by default
To:     Marc Zyngier <maz@kernel.org>
Cc:     Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Android Kernel Team <kernel-team@android.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Jisheng Zhang <Jisheng.Zhang@synaptics.com>,
        Kevin Hilman <khilman@baylibre.com>,
        John Stultz <john.stultz@linaro.org>
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On Wed, Jan 13, 2021 at 3:48 AM Marc Zyngier <maz@kernel.org> wrote:
>
> On 2021-01-13 11:44, Nicolas Saenz Julienne wrote:
> > On Thu, 2020-12-17 at 19:16 -0800, Saravana Kannan wrote:
> >> As discussed in LPC 2020, cyclic dependencies in firmware that
> >> couldn't
> >> be broken using logic was one of the last remaining reasons
> >> fw_devlink=on couldn't be set by default.
> >>
> >> This series changes fw_devlink so that when a cyclic dependency is
> >> found
> >> in firmware, the links between those devices fallback to permissive
> >> mode
> >> behavior. This way, the rest of the system still benefits from
> >> fw_devlink, but the ambiguous cases fallback to permissive mode.
> >>
> >> Setting fw_devlink=on by default brings a bunch of benefits
> >> (currently,
> >> only for systems with device tree firmware):
> >> * Significantly cuts down deferred probes.
> >> * Device probe is effectively attempted in graph order.
> >> * Makes it much easier to load drivers as modules without having to
> >>   worry about functional dependencies between modules (depmod is still
> >>   needed for symbol dependencies).
> >
> > FWIW I don't see any issues with this on Raspberry Pi 4 :).
>
> Keep bragging! ;-)
>

Yay! Thanks for confirming Nicolas.

-Saravana