linux-kernel - Re: [PATCH 1/2] ACPI / PM: Use Low Power S0 Idle on more systems

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Message-ID: <1515590661.7000.855.camel@linux.intel.com>
Date:   Wed, 10 Jan 2018 15:24:21 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Linux ACPI <linux-acpi@...r.kernel.org>
Cc:     Darren Hart <dvhart@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        Platform Driver <platform-driver-x86@...r.kernel.org>,
        Valentin Manea <valy@....ro>
Subject: Re: [PATCH 1/2] ACPI / PM: Use Low Power S0 Idle on more systems

On Wed, 2018-01-10 at 13:26 +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> Some systems don't support the ACPI_LPS0_ENTRY and ACPI_LPS0_EXIT
> functions in their Low Power S0 Idle _DSM, but still expect EC
> events to be processed in the suspend-to-idle state for power button
> wakeup (among other things) to work.  Surface Pro3 turns out to be
> one of them.
> 
> Fortunately, it still provides Low Power S0 Idle _DSM with the screen
> on/off functions supported, so modify the ACPI suspend-to-idle to use
> the Low Power S0 Idle code path for all systems supporting the
> ACPI_LPS0_ENTRY and ACPI_LPS0_EXIT or the ACPI_LPS0_SCREEN_OFF and
> ACPI_LPS0_SCREEN_ON functions in their Low Power S0 Idle _DSM.
> 
> Potentially, that will cause more systems to use suspend-to-idle by
> default, so some future corrections may be necessary if it leads
> to issues, but let it remain more straightforward for now.
 
> -#define ACPI_S2IDLE_FUNC_MASK	((1 << ACPI_LPS0_ENTRY) | (1 <<
> ACPI_LPS0_EXIT))
> +#define ACPI_LPS0_SCREEN_MASK	((1 << ACPI_LPS0_SCREEN_OFF) |
> (1 << ACPI_LPS0_SCREEN_ON))

> +#define ACPI_LPS0_S2I_MASK	((1 << ACPI_LPS0_ENTRY) | (1 <<
> ACPI_LPS0_EXIT))

Just a nitpick: Can we leave S2IDLE instead of S2I?
Would it make sense for potential code readers?

-- 
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Intel Finland Oy