Re: [PATCH 1/1] ACPI: property: Fix REF STR... reference parsing

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Hi Rafael,

On Mon, Mar 31, 2025 at 05:00:52PM +0200, Rafael J. Wysocki wrote:
> Hi Sakari,
> 
> On Mon, Mar 31, 2025 at 3:35 PM Sakari Ailus
> <sakari.ailus@linux.intel.com> wrote:
> >
> > Hi Rafael,
> >
> > On Mon, Mar 31, 2025 at 03:19:07PM +0200, Rafael J. Wysocki wrote:
> > > On Mon, Mar 31, 2025 at 2:18 PM Sakari Ailus
> > > <sakari.ailus@linux.intel.com> wrote:
> > > >
> > > > Restore parsing of ACPI data node references consisting of a device node
> > > > reference followed by one or more child data node names.
> > > >
> > > > Fixes: 9880702d123f ("ACPI: property: Support using strings in reference properties")
> > > > Cc: stable@vger.kernel.org # for 6.8 and later
> > > > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > > > ---
> > > > Hi Rafael,
> > > >
> > > > It seems that support for REF STR... references got accidentally removed
> > > > when pure STR reference were added. The former are documented in
> > > > Documentation/firmware-guide/acpi/dsd/graph.rst .
> > >
> > > It would be good to provide an ASL example that is not parsed as
> > > expected before the change and will be parsed correctly after it.
> > >
> > > Admittedly, I can't quite recall the history leading to the above
> > > commit, but this paragraphs is present in its changelog:
> > >
> > > "Also remove the mechanism allowing data nodes to be referenced
> > >  indirectly, with the help of an object reference pointing to the
> > >  "ancestor" device and a path relative to it (this mechanism is not
> > >  expected to be in use in any production platform firmware in the field)."
> > >
> > > so the change in question appears to be intentional rather than accidental.
> >
> > Right. This still continues to be documented in
> > Documentation/firmware-guide/acpi/dsd/graph.rst as noted in my previous
> > e-mail. A sample ASL snippet is can also be found in the same file. I only
> > noticed this when I tried to use such references.
> >
> > The other option indeed is to change the documentation and hope no-one
> > depends on it.
> 
> I thought that this was the original plan.

I wasn't aware of the plan. But given that no-one has complained yet,
there's a fair chance no-one will. I can post patches to switch to
string-only references.

-- 
Sakari Ailus