linux-kernel - Re: [PATCH 2/2] ACPI: let BIOS fall back to legacy handling if PRM disabled

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Date:   Fri, 2 Jul 2021 16:02:56 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Aubrey Li <aubrey.li@...ux.intel.com>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Aubrey Li <aubrey.li@...el.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Dan Williams <dan.j.williams@...el.com>
Subject: Re: [PATCH 2/2] ACPI: let BIOS fall back to legacy handling if PRM disabled

On Fri, Jul 2, 2021 at 4:02 PM Aubrey Li <aubrey.li@...ux.intel.com> wrote:
>
> On 7/2/21 7:37 PM, Rafael J. Wysocki wrote:
> > On Fri, Jul 2, 2021 at 9:03 AM Aubrey Li <aubrey.li@...el.com> wrote:
> >>
> >> Based on _OSC PRM bit, BIOS can choose switch from legacy handling
> >> to using PRM. So if CONFIG_ACPI_PRMT is disabled, this bit should
> >> not be set to let BIOS fall back to the legacy handling (such as SMI).
> >>
> >> Cc: Dan Williams <dan.j.williams@...el.com>
> >> Signed-off-by: Aubrey Li <aubrey.li@...ux.intel.com>
> >> ---
> >>  drivers/acpi/bus.c | 2 ++
> >>  1 file changed, 2 insertions(+)
> >>
> >> diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
> >> index 60fb6a84..30a3d4a 100644
> >> --- a/drivers/acpi/bus.c
> >> +++ b/drivers/acpi/bus.c
> >> @@ -303,7 +303,9 @@ static void acpi_bus_osc_negotiate_platform_control(void)
> >>
> >>         capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_HOTPLUG_OST_SUPPORT;
> >>         capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PCLPI_SUPPORT;
> >> +#ifdef CONFIG_ACPI_PRMT
> >>         capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PRM_SUPPORT;
> >> +#endif
> >
> > What about using if (IS_ENABLED()) instead of #ifdef?
>
> aha, sorry, using if (IS_ENABLED()) is better, will come up with a new version soon.

No need (see my other reply).

Thanks!