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Date: Thu, 30 Jun 2022 21:33:19 -0500 From: Mario Limonciello <mario.limonciello@....com> To: <mario.limonciello@....com>, "Rafael J. Wysocki" <rafael@...nel.org>, Pavel Machek <pavel@....cz>, Len Brown <len.brown@...el.com> CC: <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org> Subject: [PATCH v3 01/10] PM: suspend: Introduce `pm_suspend_preferred_s2idle` Many drivers in the kernel will check the FADT to determine if low power idle is supported and use this information to set up a policy decision in the driver. To abstract this information from drivers introduce a new helper symbol that can indicate this information. Signed-off-by: Mario Limonciello <mario.limonciello@....com> --- include/linux/suspend.h | 1 + kernel/power/suspend.c | 17 +++++++++++++++++ 2 files changed, 18 insertions(+) diff --git a/include/linux/suspend.h b/include/linux/suspend.h index 70f2921e2e70..9d911e026720 100644 --- a/include/linux/suspend.h +++ b/include/linux/suspend.h @@ -305,6 +305,7 @@ static inline bool idle_should_enter_s2idle(void) return unlikely(s2idle_state == S2IDLE_STATE_ENTER); } +extern bool pm_suspend_preferred_s2idle(void); extern bool pm_suspend_default_s2idle(void); extern void __init pm_states_init(void); extern void s2idle_set_ops(const struct platform_s2idle_ops *ops); diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 827075944d28..0030e7dfe6cf 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -9,6 +9,7 @@ #define pr_fmt(fmt) "PM: " fmt +#include <linux/acpi.h> #include <linux/string.h> #include <linux/delay.h> #include <linux/errno.h> @@ -61,6 +62,22 @@ static DECLARE_SWAIT_QUEUE_HEAD(s2idle_wait_head); enum s2idle_states __read_mostly s2idle_state; static DEFINE_RAW_SPINLOCK(s2idle_lock); +/** + * pm_suspend_preferred_s2idle - Check if suspend-to-idle is the preferred suspend method. + * + * Return 'true' if suspend-to-idle is preferred by the system designer for the default + * suspend method. + */ +bool pm_suspend_preferred_s2idle(void) +{ +#ifdef CONFIG_ACPI + return acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0; +#else + return false; +#endif +} +EXPORT_SYMBOL_GPL(pm_suspend_preferred_s2idle); + /** * pm_suspend_default_s2idle - Check if suspend-to-idle is the default suspend. * -- 2.34.1
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