RE: [PATCH v2 1/3] ACPI: Resolve objects on host-directed table loads

[Nikolaus Voss]

Bob,

On Fri, 14 Jun 2019, Moore, Robert wrote:
> -----Original Message-----
> From: Nikolaus Voss [mailto:nv@xxxxxxx]
> Sent: Friday, June 14, 2019 2:26 AM
> To: Rafael J. Wysocki <rafael@xxxxxxxxxx>
> Cc: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>; Len Brown <lenb@xxxxxxxxxx>; Moore, Robert <robert.moore@xxxxxxxxx>; Schmauss, Erik <erik.schmauss@xxxxxxxxx>; Jacek Anaszewski <jacek.anaszewski@xxxxxxxxx>; Pavel Machek <pavel@xxxxxx>; Dan Murphy <dmurphy@xxxxxx>; Thierry Reding <thierry.reding@xxxxxxxxx>; ACPI Devel Maling List <linux-acpi@xxxxxxxxxxxxxxx>; open list:ACPI COMPONENT ARCHITECTURE (ACPICA) <devel@xxxxxxxxxx>; linux-leds@xxxxxxxxxxxxxxx; Linux PWM List <linux-pwm@xxxxxxxxxxxxxxx>; Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>
> Subject: Re: [PATCH v2 1/3] ACPI: Resolve objects on host-directed table loads
>
> Hi Rafael,
>
> On Fri, 14 Jun 2019, Rafael J. Wysocki wrote:
> > On Wed, Jun 12, 2019 at 10:36 AM Nikolaus Voss
> > <nikolaus.voss@xxxxxxxxxxxxxxxxxxxxx> wrote:
> > > If an ACPI SSDT overlay is loaded after built-in tables have been
> > > loaded e.g. via configfs or efivar_ssdt_load() it is necessary to
> > > rewalk the namespace to resolve references. Without this, relative
> > > and absolute paths like ^PCI0.SBUS or \_SB.PCI0.SBUS are not resolved
> > > correctly.
> > >
> > > Make configfs load use the same method as efivar_ssdt_load().
> > >
> > > Signed-off-by: Nikolaus Voss <nikolaus.voss@xxxxxxxxxxxxxxxxxxxxx>
> >
> > This is fine by me, so
> >
> > Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> >
> > Or if you want me to take this patch (without the other two in the
> > series), please let me know.
>
> thanks. I think it would be the best if you take up this patch as it is 
> an independent topic. In retrospect it wasn't a good idea to put it into 
> this series.
>
> Kind regards,
> Niko
>
> I would have to ask, why is additional code needed for package 
> initialization/resolution? It already happens elsewhere in acpica. Bob

for built-in tables loaded via acpi_ex_load_table_op() everything is fine, 
because after acpi_tb_load_table() acpi_ns_walk_namespace() is called to 
resolve references.

My fix only affects tables loaded dynamically via either 
acpi_configfs driver (for debugging purposes) or efivar_ssdt_load() (to 
specify a table on the kernel's command line). They use acpi_load_table() 
to load the table from a caller-owned buffer. To resolve the references, 
it is again necessary to rewalk the namespace, which was simply missing in 
acpi_load_table().

Niko