Re: [PATCH next] ACPICA: AML Parser: Remove spurious precision from format used to dump parse trees
From: Rafael J. Wysocki
Date: Fri Mar 27 2026 - 07:21:07 EST
On Fri, Mar 27, 2026 at 11:58 AM David Laight
<david.laight.linux@xxxxxxxxx> wrote:
>
> On Fri, 27 Mar 2026 10:58:14 +0100
> "Rafael J. Wysocki" <rafael@xxxxxxxxxx> wrote:
>
> > On Fri, Mar 27, 2026 at 10:45 AM David Laight
> > <david.laight.linux@xxxxxxxxx> wrote:
> > >
> > > On Fri, 27 Mar 2026 11:28:26 +0200
> > > Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> > >
> > > > On Thu, Mar 26, 2026 at 08:18:30PM +0000, david.laight.linux@xxxxxxxxx wrote:
> > > >
> > > > > The debug code in acpi_ps_delete_parse_tree() uses ("%*.s", level * 4, " ")
> > > > > to indent traces.
> > > > > POSIX requires the empty precision be treated as zero, but the kernel treats
> > > > > is as 'no precision specified'.
> > > > > Change to ("%*s", level * 4, "") since there is additional whitespace and no
> > > > > reason to indent by one space when level is zero.
> > > >
> > > > This is cross-platform code. Does the same applies to MS VC compiler, for
> > > > example?
> > > >
> > >
> > > Everything except the linux kernel will treat "%*.s" as "%*.0s".
> > >
> > > Regardless of anything else specifying a 'precision' when printing
> > > a constant string is entirely pointless - it limits the number of
> > > characters copied from the string.
> > >
> > > Basically "%*.s" is always a typo, either for "%.*s" or "%*s".
> >
> > So this change should be made in upstream ACPICA in the first place as
> > per Documentation/driver-api/acpi/linuxized-acpica.rst.
> >
> > Would you please send a PR to the upstream ACPICA project on GH?
>
> I'd have to go through a lot of hoops to do that.
> I've never used GH.
OK, we'll go for the second option then.
> > Alternatively, someone else may make that change upstream with a
> > Suggested-by tag pointing to you.