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

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Message-ID: <f8f0b7ee-b225-eff0-cfcc-bb43e9e520dc@linux.intel.com>
Date:   Fri, 2 Jul 2021 22:02:31 +0800
From:   Aubrey Li <aubrey.li@...ux.intel.com>
To:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Aubrey Li <aubrey.li@...el.com>
Cc:     "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 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.

Thanks,
-Aubrey