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| author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2022-07-21 19:13:30 +0300 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2022-07-26 21:53:00 +0300 |
| commit | ec6c0503190417abf8b8f8e3e955ae583a4e50d4 (patch) | |
| tree | e6dfd060c5dd3b0c5033dcf16af9d31d51e64b57 /drivers/acpi/x86 | |
| parent | 1a2dcab517cbf8f58ebf1e12aea253f5df9cff80 (diff) | |
| download | linux-ec6c0503190417abf8b8f8e3e955ae583a4e50d4.tar.xz | |
ACPI: PM: x86: Print messages regarding LPS0 idle support
Because suspend-to-idle is always supported and on x86 it is the only
way to suspend the system if S3 is not supported by the platform, the
kernel attempts to enter low-power S0 idle in the suspend-to-idle flow
regardless of whether or not the ACPI_FADT_LOW_POWER_S0 flag is set in
the FADT. However, if that flag is not set, residency counters
associated with low-power S0 idle may not count and the platform may
refuse to put the EC into a low-power mode, for example.
For this reason, print diagnostic messages when the platform should
achieve significant energy savings in low-power S0 idle (because the
ACPI_FADT_LOW_POWER_S0 flag is set in the FADT) and when
suspend-to-idle becomes the default suspend method (because low-power
S0 idle should be equally or more efficient than S3, if available).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Diffstat (limited to 'drivers/acpi/x86')
| -rw-r--r-- | drivers/acpi/x86/s2idle.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/acpi/x86/s2idle.c b/drivers/acpi/x86/s2idle.c index c1e5c3de59f0..f9ac12b778e6 100644 --- a/drivers/acpi/x86/s2idle.c +++ b/drivers/acpi/x86/s2idle.c @@ -423,8 +423,10 @@ static int lps0_device_attach(struct acpi_device *adev, * line. */ if ((acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0) && - mem_sleep_default > PM_SUSPEND_MEM && !acpi_sleep_default_s3) + mem_sleep_default > PM_SUSPEND_MEM && !acpi_sleep_default_s3) { mem_sleep_current = PM_SUSPEND_TO_IDLE; + pr_info("Low-power S0 idle used by default for system suspend\n"); + } /* * Some LPS0 systems, like ASUS Zenbook UX430UNR/i7-8550U, require the |