linux-kernel - Re: [PATCH v1 2/8] ACPI: bus: Rework printing debug messages on

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Message-ID: <CAJZ5v0jgo4uCs9xcK0mKxO1yKy3NP1eubO01R7KE0G1AcBf9MQ@mail.gmail.com>
Date: Fri, 19 Dec 2025 18:20:12 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Jonathan Cameron <jonathan.cameron@...wei.com>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>, Linux ACPI <linux-acpi@...r.kernel.org>, 
	LKML <linux-kernel@...r.kernel.org>, Linux PCI <linux-pci@...r.kernel.org>, 
	Bjorn Helgaas <helgaas@...nel.org>, 
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>, Hans de Goede <hansg@...nel.org>, 
	Mario Limonciello <mario.limonciello@....com>
Subject: Re: [PATCH v1 2/8] ACPI: bus: Rework printing debug messages on _OSC errors

On Fri, Dec 19, 2025 at 1:33 PM Jonathan Cameron
<jonathan.cameron@...wei.com> wrote:
>
> On Thu, 18 Dec 2025 21:35:27 +0100
> "Rafael J. Wysocki" <rafael@...nel.org> wrote:
>
> > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> >
> > Instead of using one function, acpi_print_osc_error(), for printing a
> > debug message and dumping the _OSC request data in one go, use
> > acpi_handle_debug() directly for printing messages and a separate
> > function called acpi_dump_osc_data() for dumping the _OSC request data
> > after printing one or more of them.
> >
> > This allows the message printing in the _OSC handling code to be
> > organized so that the messages printed by it are easier to parse.
>
> Hi Rafael,
>
> Perhaps an example of the print to motivate this change clearly?
> The absence of a guid on the error string line for instance may
> or may not bother people. It's there in the dump but that comes
> after the error print I think.

Yes, it's there.

I guess I can add examples of "before" and "after" printouts to the
patch changelog.

> > Also, use %pUL for UUID printing instead of printing UUIDs as strings
> > and include the revision number into the dumped _OSC request data.
> >
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > ---
> >  drivers/acpi/bus.c |   35 ++++++++++++++++-------------------
> >  1 file changed, 16 insertions(+), 19 deletions(-)
> >
> > --- a/drivers/acpi/bus.c
> > +++ b/drivers/acpi/bus.c
> > @@ -180,18 +180,15 @@ void acpi_bus_detach_private_data(acpi_h
> >  }
> >  EXPORT_SYMBOL_GPL(acpi_bus_detach_private_data);
> >
> > -static void acpi_print_osc_error(acpi_handle handle,
> > -                              struct acpi_osc_context *context, char *error)
> > +static void acpi_dump_osc_data(acpi_handle handle, const guid_t *guid, int rev,
> > +                            struct acpi_buffer *cap)
> >  {
> > +     u32 *capbuf = cap->pointer;
> >       int i;
> >
> > -     acpi_handle_debug(handle, "(%s): %s\n", context->uuid_str, error);
> > -
> > -     pr_debug("_OSC request data:");
> > -     for (i = 0; i < context->cap.length; i += sizeof(u32))
> > -             pr_debug(" %x", *((u32 *)(context->cap.pointer + i)));
> > -
> > -     pr_debug("\n");
> > +     for (i = 0; i < cap->length / sizeof(u32); i++)
> > +             acpi_handle_debug(handle, "(%pUL, %d): capabilities DWORD %i: [%08x]\n",
> > +                               guid, rev, i, capbuf[i]);
> >  }
> >
> >  #define OSC_ERROR_MASK       (OSC_REQUEST_ERROR | OSC_INVALID_UUID_ERROR | \
> > @@ -239,8 +236,8 @@ acpi_status acpi_run_osc(acpi_handle han
> >       out_obj = output.pointer;
> >       if (out_obj->type != ACPI_TYPE_BUFFER
> >               || out_obj->buffer.length != context->cap.length) {
> > -             acpi_print_osc_error(handle, context,
> > -                     "_OSC evaluation returned wrong type");
> > +             acpi_handle_debug(handle, "_OSC evaluation returned wrong type");
> > +             acpi_dump_osc_data(handle, &guid, context->rev, &context->cap);
> >               status = AE_TYPE;
> >               goto out_kfree;
> >       }
> > @@ -252,18 +249,18 @@ acpi_status acpi_run_osc(acpi_handle han
> >
> >       if (errors) {
> >               if (errors & OSC_REQUEST_ERROR)
> > -                     acpi_print_osc_error(handle, context,
> > -                             "_OSC request failed");
> > +                     acpi_handle_debug(handle, "_OSC request failed");
> > +
> >               if (errors & OSC_INVALID_UUID_ERROR)
> > -                     acpi_print_osc_error(handle, context,
> > -                             "_OSC invalid UUID");
> > +                     acpi_handle_debug(handle, "_OSC invalid UUID");
> > +
> >               if (errors & OSC_INVALID_REVISION_ERROR)
> > -                     acpi_print_osc_error(handle, context,
> > -                             "_OSC invalid revision");
> > +                     acpi_handle_debug(handle, "_OSC invalid revision");
> > +
> >               if (errors & OSC_CAPABILITIES_MASK_ERROR)
> > -                     acpi_print_osc_error(handle, context,
> > -                             "_OSC capability bits masked");
> > +                     acpi_handle_debug(handle, "_OSC capability bits masked");
> >
> > +             acpi_dump_osc_data(handle, &guid, context->rev, &context->cap);
> >               status = AE_ERROR;
> >               goto out_kfree;
> >       }