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From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: Thu, 14 Mar 2024 09:46:43 +0100
Message-ID: <CAMuHMdV-P9nt1htpn-+jicUMA_JsOpf6mszajP9qORNweicLLw@mail.gmail.com>
Subject: Re: [PATCH] of: property: fw_devlink: Fix stupid bug in
 remote-endpoint parsing
To: Saravana Kannan <saravanak@google.com>
Cc: Rob Herring <robh+dt@kernel.org>, Frank Rowand <frowand.list@gmail.com>, 
	=?UTF-8?Q?Herv=C3=A9_Codina?= <herve.codina@bootlin.com>, 
	Luca Ceresoli <luca.ceresoli@bootlin.com>, kernel-team@android.com, 
	Rob Herring <robh@kernel.org>, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
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Hi Saravana,

On Thu, Mar 14, 2024 at 2:48=E2=80=AFAM Saravana Kannan <saravanak@google.c=
om> wrote:
> On Thu, Feb 29, 2024 at 2:11=E2=80=AFAM Geert Uytterhoeven <geert@linux-m=
68k.org> wrote:
> > On Sat, Feb 24, 2024 at 6:25=E2=80=AFAM Saravana Kannan <saravanak@goog=
le.com> wrote:
> > > Introduced a stupid bug in commit 782bfd03c3ae ("of: property: Improv=
e
> > > finding the supplier of a remote-endpoint property") due to a last mi=
nute
> > > incorrect edit of "index !=3D0" into "!index". This patch fixes it to=
 be
> > > "index > 0" to match the comment right next to it.
> > >
> > > Reported-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
> > > Link: https://lore.kernel.org/lkml/20240223171849.10f9901d@booty/
> > > Fixes: 782bfd03c3ae ("of: property: Improve finding the supplier of a=
 remote-endpoint property")
> > > Signed-off-by: Saravana Kannan <saravanak@google.com>
> >
> > Thanks for your patch!
> >
> > > --- a/drivers/of/property.c
> > > +++ b/drivers/of/property.c
> > > @@ -1304,7 +1304,7 @@ static struct device_node *parse_remote_endpoin=
t(struct device_node *np,
> > >                                                  int index)
> > >  {
> > >         /* Return NULL for index > 0 to signify end of remote-endpoin=
ts. */
> > > -       if (!index || strcmp(prop_name, "remote-endpoint"))
> > > +       if (index > 0 || strcmp(prop_name, "remote-endpoint"))
> > >                 return NULL;
> > >
> > >         return of_graph_get_remote_port_parent(np);
> > > --
> > > 2.44.0.rc0.258.g7320e95886-goog
> >
> > After this, the "Fixed dependency cycle" messages I reported to be
> > gone in [1] are back.
> >
> > In fact, they are slightly different, and there are now even more of th=
em:
> >
> > -platform fea80000.csi2: Fixed dependency cycle(s) with
> > /soc/video@e6ef7000/ports/port@1/endpoint@0
> > -platform fea80000.csi2: Fixed dependency cycle(s) with
> > /soc/video@e6ef6000/ports/port@1/endpoint@0
> > -platform fea80000.csi2: Fixed dependency cycle(s) with
> > /soc/video@e6ef5000/ports/port@1/endpoint@0
> > -platform fea80000.csi2: Fixed dependency cycle(s) with
> > /soc/video@e6ef4000/ports/port@1/endpoint@0
> > -platform fea80000.csi2: Fixed dependency cycle(s) with
> > /soc/video@e6ef3000/ports/port@1/endpoint@0
> > -platform fea80000.csi2: Fixed dependency cycle(s) with
> > /soc/video@e6ef2000/ports/port@1/endpoint@0
> > -platform fea80000.csi2: Fixed dependency cycle(s) with
> > /soc/video@e6ef1000/ports/port@1/endpoint@0
> > -platform fea80000.csi2: Fixed dependency cycle(s) with
> > /soc/video@e6ef0000/ports/port@1/endpoint@0
> > -platform feaa0000.csi2: Fixed dependency cycle(s) with
> > /soc/video@e6ef3000/ports/port@1/endpoint@2
> > -platform feaa0000.csi2: Fixed dependency cycle(s) with
> > /soc/video@e6ef2000/ports/port@1/endpoint@2
> > -platform feaa0000.csi2: Fixed dependency cycle(s) with
> > /soc/video@e6ef1000/ports/port@1/endpoint@2
> > -platform feaa0000.csi2: Fixed dependency cycle(s) with
> > /soc/video@e6ef0000/ports/port@1/endpoint@2
> > -platform fead0000.hdmi: Fixed dependency cycle(s) with
> > /soc/sound@ec500000/ports/port@1/endpoint
> > -platform feae0000.hdmi: Fixed dependency cycle(s) with
> > /soc/sound@ec500000/ports/port@2/endpoint
> > -platform feb00000.display: Fixed dependency cycle(s) with
> > /soc/hdmi@feae0000/ports/port@0/endpoint
> > -platform feb00000.display: Fixed dependency cycle(s) with
> > /soc/hdmi@fead0000/ports/port@0/endpoint
> > -platform hdmi0-out: Fixed dependency cycle(s) with
> > /soc/hdmi@fead0000/ports/port@1/endpoint
> > -platform hdmi1-out: Fixed dependency cycle(s) with
> > /soc/hdmi@feae0000/ports/port@1/endpoint
> > -platform vga-encoder: Fixed dependency cycle(s) with /vga/port/endpoin=
t
> > -platform vga-encoder: Fixed dependency cycle(s) with
> > /soc/display@feb00000/ports/port@0/endpoint
> > +platform e6ef0000.video: Fixed dependency cycle(s) with /soc/csi2@feaa=
0000
> > +platform e6ef0000.video: Fixed dependency cycle(s) with /soc/csi2@fea8=
0000
> > +platform e6ef1000.video: Fixed dependency cycle(s) with /soc/csi2@feaa=
0000
> > +platform e6ef1000.video: Fixed dependency cycle(s) with /soc/csi2@fea8=
0000
> > +platform e6ef2000.video: Fixed dependency cycle(s) with /soc/csi2@feaa=
0000
> > +platform e6ef2000.video: Fixed dependency cycle(s) with /soc/csi2@fea8=
0000
> > +platform e6ef3000.video: Fixed dependency cycle(s) with /soc/csi2@feaa=
0000
> > +platform e6ef3000.video: Fixed dependency cycle(s) with /soc/csi2@fea8=
0000
> > +platform e6ef4000.video: Fixed dependency cycle(s) with /soc/csi2@fea8=
0000
> > +platform e6ef5000.video: Fixed dependency cycle(s) with /soc/csi2@fea8=
0000
> > +platform e6ef6000.video: Fixed dependency cycle(s) with /soc/csi2@fea8=
0000
> > +platform e6ef7000.video: Fixed dependency cycle(s) with /soc/csi2@fea8=
0000
> > +platform ec500000.sound: Fixed dependency cycle(s) with /soc/hdmi@feae=
0000
> > +platform ec500000.sound: Fixed dependency cycle(s) with /soc/hdmi@fead=
0000
> > +platform ec500000.sound: Fixed dependency cycle(s) with
> > /soc/i2c@e6510000/codec@10
> > +platform e6ef7000.video: Fixed dependency cycle(s) with /soc/csi2@fea8=
0000
> > +platform e6ef6000.video: Fixed dependency cycle(s) with /soc/csi2@fea8=
0000
> > +platform e6ef5000.video: Fixed dependency cycle(s) with /soc/csi2@fea8=
0000
> > +platform e6ef4000.video: Fixed dependency cycle(s) with /soc/csi2@fea8=
0000
> > +platform e6ef3000.video: Fixed dependency cycle(s) with /soc/csi2@fea8=
0000
> > +platform e6ef2000.video: Fixed dependency cycle(s) with /soc/csi2@fea8=
0000
> > +platform e6ef1000.video: Fixed dependency cycle(s) with /soc/csi2@fea8=
0000
> > +platform e6ef0000.video: Fixed dependency cycle(s) with /soc/csi2@fea8=
0000
> > +platform fea80000.csi2: Fixed dependency cycle(s) with /soc/video@e6ef=
7000
> > +platform fea80000.csi2: Fixed dependency cycle(s) with /soc/video@e6ef=
6000
> > +platform fea80000.csi2: Fixed dependency cycle(s) with /soc/video@e6ef=
5000
> > +platform fea80000.csi2: Fixed dependency cycle(s) with /soc/video@e6ef=
4000
> > +platform fea80000.csi2: Fixed dependency cycle(s) with /soc/video@e6ef=
3000
> > +platform fea80000.csi2: Fixed dependency cycle(s) with /soc/video@e6ef=
2000
> > +platform fea80000.csi2: Fixed dependency cycle(s) with /soc/video@e6ef=
1000
> > +platform fea80000.csi2: Fixed dependency cycle(s) with /soc/video@e6ef=
0000
> > +platform fea80000.csi2: Fixed dependency cycle(s) with
> > /soc/i2c@e66d8000/video-receiver@70
> > +platform e6ef3000.video: Fixed dependency cycle(s) with /soc/csi2@feaa=
0000
> > +platform e6ef2000.video: Fixed dependency cycle(s) with /soc/csi2@feaa=
0000
> > +platform e6ef1000.video: Fixed dependency cycle(s) with /soc/csi2@feaa=
0000
> > +platform e6ef0000.video: Fixed dependency cycle(s) with /soc/csi2@feaa=
0000
> > +platform feaa0000.csi2: Fixed dependency cycle(s) with /soc/video@e6ef=
3000
> > +platform feaa0000.csi2: Fixed dependency cycle(s) with /soc/video@e6ef=
2000
> > +platform feaa0000.csi2: Fixed dependency cycle(s) with /soc/video@e6ef=
1000
> > +platform feaa0000.csi2: Fixed dependency cycle(s) with /soc/video@e6ef=
0000
> > +platform feaa0000.csi2: Fixed dependency cycle(s) with
> > /soc/i2c@e66d8000/video-receiver@70
> > +platform ec500000.sound: Fixed dependency cycle(s) with /soc/hdmi@fead=
0000
> > +platform fead0000.hdmi: Fixed dependency cycle(s) with /soc/sound@ec50=
0000
> > +platform fead0000.hdmi: Fixed dependency cycle(s) with /soc/display@fe=
b00000
> > +platform ec500000.sound: Fixed dependency cycle(s) with /soc/hdmi@feae=
0000
> > +platform feae0000.hdmi: Fixed dependency cycle(s) with /soc/sound@ec50=
0000
> > +platform feae0000.hdmi: Fixed dependency cycle(s) with /soc/display@fe=
b00000
> > +platform feae0000.hdmi: Fixed dependency cycle(s) with /soc/display@fe=
b00000
> > +platform fead0000.hdmi: Fixed dependency cycle(s) with /soc/display@fe=
b00000
> > +platform feb00000.display: Fixed dependency cycle(s) with /soc/hdmi@fe=
ae0000
> > +platform feb00000.display: Fixed dependency cycle(s) with /soc/hdmi@fe=
ad0000
> > +platform cvbs-in: Fixed dependency cycle(s) with
> > /soc/i2c@e66d8000/video-receiver@70
> > +platform hdmi-in: Fixed dependency cycle(s) with
> > /soc/i2c@e66d8000/video-receiver@70
> > +platform fead0000.hdmi: Fixed dependency cycle(s) with /hdmi0-out
> > +platform hdmi0-out: Fixed dependency cycle(s) with /soc/hdmi@fead0000
> > +platform feae0000.hdmi: Fixed dependency cycle(s) with /hdmi1-out
> > +platform hdmi1-out: Fixed dependency cycle(s) with /soc/hdmi@feae0000
> > +platform vga: Fixed dependency cycle(s) with /vga-encoder
> > +platform feb00000.display: Fixed dependency cycle(s) with /vga-encoder
> > +platform vga-encoder: Fixed dependency cycle(s) with /vga
> > +platform vga-encoder: Fixed dependency cycle(s) with /soc/display@feb0=
0000
> >
> > -i2c 2-0010: Fixed dependency cycle(s) with
> > /soc/sound@ec500000/ports/port@0/endpoint
> > +platform ec500000.sound: Fixed dependency cycle(s) with
> > /soc/i2c@e6510000/codec@10
> >
> > -i2c 4-0070: Fixed dependency cycle(s) with
> > /soc/csi2@fea80000/ports/port@0/endpoint
> > -i2c 4-0070: Fixed dependency cycle(s) with
> > /soc/csi2@feaa0000/ports/port@0/endpoint
> > -i2c 4-0070: Fixed dependency cycle(s) with /hdmi-in/port/endpoint
> > -i2c 4-0070: Fixed dependency cycle(s) with /cvbs-in/port/endpoint
> > +platform feaa0000.csi2: Fixed dependency cycle(s) with
> > /soc/i2c@e66d8000/video-receiver@70
> > +platform fea80000.csi2: Fixed dependency cycle(s) with
> > /soc/i2c@e66d8000/video-receiver@70
> > +i2c 4-0070: Fixed dependency cycle(s) with /soc/csi2@fea80000
> > +i2c 4-0070: Fixed dependency cycle(s) with /soc/csi2@feaa0000
> >
> > I guess all of that is expected?
>
> Hi Geert,
>
> Greg has picked up my "post-init-providers" series in his driver core.

You mean https://lore.kernel.org/all/20240305050458.1400667-2-saravanak@goo=
gle.com/?

> Once you pull that in, you should be able to use the
> post-init-providers property to break these cycles. Basically treat it
> like any other supplier binding, but use it to mark the link in the
> cycle that's not real. For the remote-endpoints case, you need to list
> property at the device level. Not the endpoint, port or ports nodes.
>
> Once you add this property, you should see an increase in the number
> of device links that are present after all device probing is done.
> Also, a bunch of existing device links should get converted from
> sync_state_only device links to normal managed device links. Meaning,
> the sync_state_only file under those /class/devlink/<device-link-x>/
> folder should change from "1" to "0".
>
> If that's what you see and it works, then go ahead and send out a
> patch so that the boards you care about have a more
> deterministic/stable probe/suspend/resume ordering.

You mean we have to add additional properties to the DTS?
What about compatibility with old DTBs?

Where are the DT bindings for "post-init-providers"?
I see it was part of earlier submissions, but I cannot find any evidence
they have ever been accepted by the DT maintainers?

Thanks!

Gr{oetje,eeting}s,

                        Geert

--=20
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k=
org

In personal conversations with technical people, I call myself a hacker. Bu=
t
when I'm talking to journalists I just say "programmer" or something like t=
hat.
                                -- Linus Torvalds