Re: [Patch v7 01/18] ACPI, irq: fix regression casued by 6b9fb7082409

[Bjorn Helgaas <bhelgaas@google.com>]

The subject should describe the change you're making.  "Fix regression
caused by xxx" doesn't say anything about what the patch does.

On Sun, Oct 26, 2014 at 11:21 PM, Jiang Liu <jiang.liu@linux.intel.com> wrote:
> When IOAPIC is disabled, acpi_gsi_to_irq() should return gsi directly
> instead of calling mp_map_gsi_to_irq() to translate gsi to IRQ by IOAPIC.

I don't know what the convention is or if there even is one, but "GSI"
is even more of an acronym than "IRQ", so I'd capitalize it.

> It fixes https://bugzilla.kernel.org/show_bug.cgi?id=84381.

A line like the following may be useful to those who have to backport this.

Fixes: 6b9fb7082409 ("x86, ACPI, irq: Consolidate algorithm of mapping
(ioapic, pin) to IRQ number")

> Reported-by: Thomas Richter <thor@math.tu-berlin.de>
> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
> Cc: rui.zhang@intel.com
> Cc: <stable@vger.kernel.org> # 3.17
> ---
>  arch/x86/kernel/acpi/boot.c |   13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
> index b436fc735aa4..eceba9d9e116 100644
> --- a/arch/x86/kernel/acpi/boot.c
> +++ b/arch/x86/kernel/acpi/boot.c
> @@ -604,14 +604,19 @@ void __init acpi_pic_sci_set_trigger(unsigned int irq, u16 trigger)
>
>  int acpi_gsi_to_irq(u32 gsi, unsigned int *irqp)
>  {
> -       int irq = mp_map_gsi_to_irq(gsi, IOAPIC_MAP_ALLOC | IOAPIC_MAP_CHECK);
> +       int irq;
>
> -       if (irq >= 0) {
> +       if (acpi_irq_model == ACPI_IRQ_MODEL_PIC) {
> +               *irqp = gsi;
> +       } else {
> +               irq = mp_map_gsi_to_irq(gsi,
> +                                       IOAPIC_MAP_ALLOC | IOAPIC_MAP_CHECK);
> +               if (irq < 0)
> +                       return -1;
>                 *irqp = irq;
> -               return 0;
>         }
>
> -       return -1;
> +       return 0;
>  }
>  EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);
>
> --
> 1.7.10.4
>