linux-kernel - Re: [PATCH v2 1/9] PM: domains: Delete usage of driver_deferred_probe_check

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Message-ID: <YrKhkmj3jCQA39X/@atomide.com>
Date:   Wed, 22 Jun 2022 07:58:58 +0300
From:   Tony Lindgren <tony@...mide.com>
To:     Saravana Kannan <saravanak@...gle.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Kevin Hilman <khilman@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
        Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        Andrew Lunn <andrew@...n.ch>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        David Ahern <dsahern@...nel.org>, kernel-team@...roid.com,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        iommu@...ts.linux-foundation.org, netdev@...r.kernel.org,
        linux-gpio@...r.kernel.org,
        Geert Uytterhoeven <geert@...ux-m68k.org>
Subject: Re: [PATCH v2 1/9] PM: domains: Delete usage of
 driver_deferred_probe_check_state()

Hi,

* Saravana Kannan <saravanak@...gle.com> [220621 19:29]:
> On Tue, Jun 21, 2022 at 12:28 AM Tony Lindgren <tony@...mide.com> wrote:
> >
> > Hi,
> >
> > * Saravana Kannan <saravanak@...gle.com> [700101 02:00]:
> > > Now that fw_devlink=on by default and fw_devlink supports
> > > "power-domains" property, the execution will never get to the point
> > > where driver_deferred_probe_check_state() is called before the supplier
> > > has probed successfully or before deferred probe timeout has expired.
> > >
> > > So, delete the call and replace it with -ENODEV.
> >
> > Looks like this causes omaps to not boot in Linux next.
> 
> Can you please point me to an example DTS I could use for debugging
> this? I'm assuming you are leaving fw_devlink=on and not turning it
> off or putting it in permissive mode.

Sure, this seems to happen at least with simple-pm-bus as the top
level interconnect with a configured power-domains property:

$ git grep -A10 "ocp {" arch/arm/boot/dts/*.dtsi | grep -B3 -A4 simple-pm-bus

This issue is no directly related fw_devlink. It is a side effect of
removing driver_deferred_probe_check_state(). We no longer return
-EPROBE_DEFER at the end of driver_deferred_probe_check_state().

> > On platform_probe() genpd_get_from_provider() returns
> > -ENOENT.
> 
> This error is with the series I assume?

On the first probe genpd_get_from_provider() will return -ENOENT in
both cases. The list is empty on the first probe and there are no
genpd providers at this point.

Earlier with driver_deferred_probe_check_state(), the initial -ENOENT
ends up getting changed to -EPROBE_DEFER at the end of
driver_deferred_probe_check_state(), we are now missing that.

Regards,

Tony