From: David Gibson <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org>
To: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: "Uwe Kleine-König"
<uwe-rXY34ruvC2xidJT2blvkqNi2O/JbrIOy@public.gmane.org>,
devicetree-compiler-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
entwicklung-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org,
"Uwe Kleine-König"
<u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Subject: Re: [PATCH v2] write_propval_string: Use a list of strings instead of "\0" in a string
Date: Wed, 3 May 2023 23:43:45 +1000 [thread overview]
Message-ID: <ZFJlESnMYNI/jmHr@yekko> (raw)
In-Reply-To: <CAL_JsqJ9QManUTkOpgaE85b-uVB_JQZGsLXdJCz7_5J_3Aqq2g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
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On Mon, May 01, 2023 at 01:43:22PM -0500, Rob Herring wrote:
> On Sat, Apr 29, 2023 at 1:52 AM David Gibson
> <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org> wrote:
> >
> > On Fri, Apr 28, 2023 at 01:32:17PM +0200, Uwe Kleine-König wrote:
> > > From: Uwe Kleine-König <u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> > >
> > > A string that contains '\0' can be written as a list of strings e.g.
> > >
> > > clock-names = "di0_pll\0di1_pll\0di0_sel\0di1_sel\0di2_sel\0di3_sel\0di0\0di1";
> > >
> > > is equivalent to
> > >
> > > clock-names = "di0_pll", "di1_pll", "di0_sel", "di1_sel", "di2_sel", "di3_sel", "di0", "di1";
> > >
> > > The latter is easier to read, to use this format instead.
> > >
> > > Two test files are adapted accordingly to keep the test suite happy.
> > >
> > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> > > ---
> > > Changes since (implicit) v1, sent with Message-Id:
> > > 20230426182405.572729-1-u.kleine-koenig-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org:
> > >
> > > - Adapt the test suite
> > >
> > > tests/type-preservation.dt.yaml | 2 +-
> > > tests/type-preservation.dts | 2 +-
> > > treesource.c | 2 +-
> > > 3 files changed, 3 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/tests/type-preservation.dt.yaml b/tests/type-preservation.dt.yaml
> > > index a0cc64cc4b69..e238d395aa02 100644
> > > --- a/tests/type-preservation.dt.yaml
> > > +++ b/tests/type-preservation.dt.yaml
> > > @@ -12,7 +12,7 @@
> > > int16-matrix: [!u16 [0x1234, 0x5678], [0x90ab, 0xcdef]]
> > > int64: [!u64 [0x200000000]]
> > > int64-array: [!u64 [0x100000000, 0x0]]
> > > - a-string-with-nulls: ["foo\0bar", "baz"]
> > > + a-string-array: ["foo", "bar", "baz"]
> >
> >
> > Ah. I was afraid of this. So "fixing" the test highlights another
> > problem. It's pretty clear to me that the whole point of this test is
> > to test the preservation of the internal \0, as distinct from the
> > separate strings later in there. So, this is exercising an edge case
> > of the typing markers we now add.
> >
> > Now.. personally, I've never been particularly convinced that the type
> > preservation stuff was a particularly good idea. It will never be
> > perfect, and it can give a misleading impression that information is
> > preserved into the dtb which isn't. But, it's pretty well established
> > now, and I assume people had reasons for wanting it.
>
> I don't really think so. It was a side effect of adding the yaml
> support AFAICT. Before commit 32b9c6130762 ("Preserve datatype markers
> when emitting dts format"), any '\0' was not maintained.
Right, which also introduced this test, presumbly to verify those
semantics.
> Speaking of the YAML output, at least for dtschema, it is no longer
> being used with using dtb format directly for over a year now. Support
> for yaml encoding in dtschema was removed completely in the January
> release. Perhaps in dtc it should be deprecated for some time if not
> just outright removed. I'm not aware of anyone else using it.
Oh, that's good to hear. I've long thought the yaml output was a bad
idea, because it makes people think the dtb encodes type information
which it doesn't and can't.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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prev parent reply other threads:[~2023-05-03 13:43 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-28 11:32 [PATCH v2] write_propval_string: Use a list of strings instead of "\0" in a string Uwe Kleine-König
[not found] ` <20230428113217.744447-1-uwe-rXY34ruvC2xidJT2blvkqNi2O/JbrIOy@public.gmane.org>
2023-04-29 6:29 ` David Gibson
2023-04-30 13:23 ` Uwe Kleine-König
2023-05-01 18:43 ` Rob Herring
[not found] ` <CAL_JsqJ9QManUTkOpgaE85b-uVB_JQZGsLXdJCz7_5J_3Aqq2g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2023-05-03 13:43 ` David Gibson [this message]
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