From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Saravana Kannan <saravanak@google.com>
Cc: Tony Lindgren <tony@atomide.com>, Rob Herring <robh@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Kevin Hilman <khilman@kernel.org>,
Ulf Hansson <ulf.hansson@linaro.org>,
Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
Andrew Lunn <andrew@lunn.ch>,
Heiner Kallweit <hkallweit1@gmail.com>,
Russell King <linux@armlinux.org.uk>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Linus Walleij <linus.walleij@linaro.org>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
David Ahern <dsahern@kernel.org>,
Android Kernel Team <kernel-team@android.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux PM list <linux-pm@vger.kernel.org>,
Linux IOMMU <iommu@lists.linux-foundation.org>,
netdev <netdev@vger.kernel.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
Alexander Stein <alexander.stein@ew.tq-group.com>
Subject: Re: [PATCH v2 1/9] PM: domains: Delete usage of driver_deferred_probe_check_state()
Date: Fri, 1 Jul 2022 09:38:55 +0200 [thread overview]
Message-ID: <CAMuHMdW78nybK8LH2cDpM_0TCF-==QojaW8rKjudUhfJWNO0jA@mail.gmail.com> (raw)
In-Reply-To: <CAGETcx8c+P0r6ARmhv+ERaz9zAGBOVJQu3bSDXELBycEGfkYQw@mail.gmail.com>
Hi Saravana,
On Fri, Jul 1, 2022 at 1:11 AM Saravana Kannan <saravanak@google.com> wrote:
> On Mon, Jun 27, 2022 at 2:10 AM Tony Lindgren <tony@atomide.com> wrote:
> > * Saravana Kannan <saravanak@google.com> [220623 08:17]:
> > > On Thu, Jun 23, 2022 at 12:01 AM Tony Lindgren <tony@atomide.com> wrote:
> > > > * Saravana Kannan <saravanak@google.com> [220622 19:05]:
> > > > > On Tue, Jun 21, 2022 at 9:59 PM Tony Lindgren <tony@atomide.com> wrote:
> > > > > > 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().
> > > > >
> > > > > Yes, I understand the issue. But driver_deferred_probe_check_state()
> > > > > was deleted because fw_devlink=on should have short circuited the
> > > > > probe attempt with an -EPROBE_DEFER before reaching the bus/driver
> > > > > probe function and hitting this -ENOENT failure. That's why I was
> > > > > asking the other questions.
> > > >
> > > > OK. So where is the -EPROBE_DEFER supposed to happen without
> > > > driver_deferred_probe_check_state() then?
> > >
> > > device_links_check_suppliers() call inside really_probe() would short
> > > circuit and return an -EPROBE_DEFER if the device links are created as
> > > expected.
> >
> > OK
> >
> > > > Hmm so I'm not seeing any supplier for the top level ocp device in
> > > > the booting case without your patches. I see the suppliers for the
> > > > ocp child device instances only.
> > >
> > > Hmmm... this is strange (that the device link isn't there), but this
> > > is what I suspected.
> >
> > Yup, maybe it's because of the supplier being a device in the child
> > interconnect for the ocp.
>
> Ugh... yeah, this is why the normal (not SYNC_STATE_ONLY) device link
> isn't being created.
>
> So the aggregated view is something like (I had to set tabs = 4 space
> to fit it within 80 cols):
>
> ocp: ocp { <========================= Consumer
> compatible = "simple-pm-bus";
> power-domains = <&prm_per>; <=========== Supplier ref
>
> l4_wkup: interconnect@44c00000 {
> compatible = "ti,am33xx-l4-wkup", "simple-pm-bus";
>
> segment@200000 { /* 0x44e00000 */
> compatible = "simple-pm-bus";
>
> target-module@0 { /* 0x44e00000, ap 8 58.0 */
> compatible = "ti,sysc-omap4", "ti,sysc";
>
> prcm: prcm@0 {
> compatible = "ti,am3-prcm", "simple-bus";
>
> prm_per: prm@c00 { <========= Actual Supplier
> compatible = "ti,am3-prm-inst", "ti,omap-prm-inst";
> };
> };
> };
> };
> };
> };
>
> The power-domain supplier is the great-great-great-grand-child of the
> consumer. It's not clear to me how this is valid. What does it even
> mean?
>
> Rob, is this considered a valid DT?
>
> Geert, thoughts on whether this is a correct use of simple-pm-bus device?
Well, if the hardware is wired that way...
It's not that dissimilar from CPU cores, and interrupt and GPIO
controllers in power domains and clocked by controllable clocks:
you can cut the branch you're sitting on, and you have to be careful
when going to sleep, and make sure your wake-up sources are still
functional.
> Also, how is the power domain attach/get working in this case? As far
> as I can tell, at least for "simple-pm-bus" devices, the pm domain
> attachment is happening under:
> really_probe() -> call_driver_probe -> platform_probe() ->
> dev_pm_domain_attach()
>
> So, how is the pm domain attach succeeding in the first place without
> my changes?
That's a software thing ;-)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2022-07-01 7:46 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-01 7:06 [PATCH v2 0/9] deferred_probe_timeout logic clean up Saravana Kannan
2022-06-01 7:06 ` [PATCH v2 1/9] PM: domains: Delete usage of driver_deferred_probe_check_state() Saravana Kannan
2022-06-09 11:44 ` Ulf Hansson
2022-06-09 19:29 ` Saravana Kannan
2022-06-21 7:28 ` Tony Lindgren
2022-06-21 19:34 ` Saravana Kannan
2022-06-22 4:58 ` Tony Lindgren
2022-06-22 19:09 ` Saravana Kannan
2022-06-23 7:01 ` Tony Lindgren
2022-06-23 8:21 ` Saravana Kannan
2022-06-27 9:10 ` Tony Lindgren
2022-06-30 23:10 ` Saravana Kannan
2022-06-30 23:26 ` Rob Herring
2022-06-30 23:30 ` Saravana Kannan
2022-07-01 5:33 ` Tony Lindgren
2022-07-01 6:12 ` Tony Lindgren
2022-07-01 8:10 ` Saravana Kannan
2022-07-01 8:26 ` Saravana Kannan
2022-07-01 13:00 ` Tony Lindgren
2022-07-12 7:12 ` Tony Lindgren
2022-07-13 0:49 ` Saravana Kannan
2022-07-13 8:06 ` Tony Lindgren
2022-07-01 15:08 ` Sudeep Holla
2022-07-01 19:13 ` Saravana Kannan
2022-07-05 8:44 ` Saravana Kannan
2022-07-01 7:38 ` Geert Uytterhoeven [this message]
2022-06-23 12:08 ` Alexander Stein
2022-07-01 0:37 ` Saravana Kannan
2022-07-01 6:01 ` (EXT) " Alexander Stein
2022-07-01 7:02 ` Saravana Kannan
2022-07-04 7:07 ` (EXT) " Alexander Stein
2022-07-05 1:24 ` Saravana Kannan
2022-07-06 13:02 ` Re: " Alexander Stein
2022-07-13 0:45 ` Saravana Kannan
2022-07-14 6:41 ` Alexander Stein
2022-07-15 22:08 ` Saravana Kannan
2022-07-01 7:30 ` Geert Uytterhoeven
2022-06-01 7:06 ` [PATCH v2 2/9] pinctrl: devicetree: " Saravana Kannan
2022-06-01 7:06 ` [PATCH v2 3/9] net: mdio: " Saravana Kannan
2022-07-05 9:11 ` Geert Uytterhoeven
2022-07-13 1:40 ` Saravana Kannan
2022-07-13 11:39 ` Geert Uytterhoeven
2022-08-15 8:38 ` Geert Uytterhoeven
2022-06-01 7:07 ` [PATCH v2 4/9] driver core: Add wait_for_init_devices_probe helper function Saravana Kannan
2022-06-01 7:07 ` [PATCH v2 5/9] net: ipconfig: Relax fw_devlink if we need to mount a network rootfs Saravana Kannan
2022-06-01 7:07 ` [PATCH v2 6/9] Revert "driver core: Set default deferred_probe_timeout back to 0." Saravana Kannan
2022-07-20 17:31 ` Geert Uytterhoeven
2022-07-20 19:01 ` Saravana Kannan
2022-07-21 8:40 ` Geert Uytterhoeven
2022-06-01 7:07 ` [PATCH v2 7/9] driver core: Set fw_devlink.strict=1 by default Saravana Kannan
2022-06-22 7:47 ` Sascha Hauer
2022-06-22 8:44 ` Linus Walleij
2022-06-22 10:52 ` Andy Shevchenko
2022-06-22 11:18 ` Sascha Hauer
2022-06-22 19:40 ` Saravana Kannan
2022-06-22 20:35 ` Saravana Kannan
2022-06-22 22:30 ` Saravana Kannan
2022-06-28 13:09 ` Linus Walleij
2022-06-01 7:07 ` [PATCH v2 8/9] iommu/of: Delete usage of driver_deferred_probe_check_state() Saravana Kannan
2022-08-19 14:26 ` Jean-Philippe Brucker
2022-06-01 7:07 ` [PATCH v2 9/9] driver core: Delete driver_deferred_probe_check_state() Saravana Kannan
2022-06-07 18:07 ` [PATCH v2 0/9] deferred_probe_timeout logic clean up Geert Uytterhoeven
2022-06-08 0:55 ` Saravana Kannan
2022-06-08 4:17 ` Saravana Kannan
2022-06-08 10:25 ` Geert Uytterhoeven
2022-06-08 18:12 ` Saravana Kannan
2022-06-08 18:47 ` Geert Uytterhoeven
2022-06-08 21:07 ` Saravana Kannan
2022-06-08 22:49 ` Jakub Kicinski
2022-06-08 23:15 ` Saravana Kannan
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