linux-kernel - Re: [PATCH] ACPI: GED: add support for _Exx /

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Date:   Tue, 26 May 2020 13:12:33 +0200
From:   Ard Biesheuvel <ardb@...nel.org>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Stable <stable@...r.kernel.org>
Subject: Re: [PATCH] ACPI: GED: add support for _Exx / _Lxx handler methods

Hello Rafael,

I spotted an issue with this patch. Please see below.


On Fri, 15 May 2020 at 18:32, Rafael J. Wysocki <rafael@...nel.org> wrote:
>
> On Fri, May 15, 2020 at 11:37 AM Ard Biesheuvel <ardb@...nel.org> wrote:
> >
> > Per the ACPI spec, interrupts in the range [0, 255] may be handled
> > in AML using individual methods whose naming is based on the format
> > _Exx or _Lxx, where xx is the hex representation of the interrupt
> > index.
> >
> > Add support for this missing feature to our ACPI GED driver.
> >
> > Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>
> > Cc: Len Brown <lenb@...nel.org>
> > Cc: linux-acpi@...r.kernel.org
> > Cc: <stable@...r.kernel.org> # v4.9+
> > Signed-off-by: Ard Biesheuvel <ardb@...nel.org>
> > ---
> >  drivers/acpi/evged.c | 22 +++++++++++++++++---
> >  1 file changed, 19 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/acpi/evged.c b/drivers/acpi/evged.c
> > index aba0d0027586..6d7a522952bf 100644
> > --- a/drivers/acpi/evged.c
> > +++ b/drivers/acpi/evged.c
> > @@ -79,6 +79,8 @@ static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares,
> >         struct resource r;
> >         struct acpi_resource_irq *p = &ares->data.irq;
> >         struct acpi_resource_extended_irq *pext = &ares->data.extended_irq;
> > +       char ev_name[5];
> > +       u8 trigger;
> >
> >         if (ares->type == ACPI_RESOURCE_TYPE_END_TAG)
> >                 return AE_OK;
> > @@ -87,14 +89,28 @@ static acpi_status acpi_ged_request_interrupt(struct acpi_resource *ares,
> >                 dev_err(dev, "unable to parse IRQ resource\n");
> >                 return AE_ERROR;
> >         }
> > -       if (ares->type == ACPI_RESOURCE_TYPE_IRQ)
> > +       if (ares->type == ACPI_RESOURCE_TYPE_IRQ) {
> >                 gsi = p->interrupts[0];
> > -       else
> > +               trigger = p->triggering;
> > +       } else {
> >                 gsi = pext->interrupts[0];
> > +               trigger = p->triggering;

This should be 'pext->triggering' instead.

In practice, it doesn't matter, since p and pext point to the same
union, and the 'triggering' field happens to be at the same offset.
But it should still be fixed, of course.

Would you prefer a followup patch? Or can you fix it locally?


> > +       }
> >
> >         irq = r.start;
> >
> > -       if (ACPI_FAILURE(acpi_get_handle(handle, "_EVT", &evt_handle))) {
> > +       switch (gsi) {
> > +       case 0 ... 255:
> > +               sprintf(ev_name, "_%c%02hhX",
> > +                       trigger == ACPI_EDGE_SENSITIVE ? 'E' : 'L', gsi);
> > +
> > +               if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle)))
> > +                       break;
> > +               /* fall through */
> > +       default:
> > +               if (ACPI_SUCCESS(acpi_get_handle(handle, "_EVT", &evt_handle)))
> > +                       break;
> > +
> >                 dev_err(dev, "cannot locate _EVT method\n");
> >                 return AE_ERROR;
> >         }
> > --
>
> Applied as 5.8 material, thanks!