This is a note to let you know that I've just added the patch titled rtc: rtc-cmos: Do not check ACPI_FADT_LOW_POWER_S0 to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: rtc-rtc-cmos-do-not-check-acpi_fadt_low_power_s0.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit c5d36d39a4187f66b478a088b0ecaba0ea08585d Author: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Date: Mon Aug 8 20:23:59 2022 +0200 rtc: rtc-cmos: Do not check ACPI_FADT_LOW_POWER_S0 [ Upstream commit 6492fed7d8c95f53b0b804ef541324d924d95d41 ] The ACPI_FADT_LOW_POWER_S0 flag merely means that it is better to use low-power S0 idle on the given platform than S3 (provided that the latter is supported) and it doesn't preclude using either of them (which of them will be used depends on the choices made by user space). For this reason, there is no benefit from checking that flag in use_acpi_alarm_quirks(). First off, it cannot be a bug to do S3 with use_acpi_alarm set, because S3 can be used on systems with ACPI_FADT_LOW_POWER_S0 and it must work if really supported, so the ACPI_FADT_LOW_POWER_S0 check is not needed to protect the S3-capable systems from failing. Second, suspend-to-idle can be carried out on a system with ACPI_FADT_LOW_POWER_S0 unset and it is expected to work, so if setting use_acpi_alarm is needed to handle that case correctly, it should be set regardless of the ACPI_FADT_LOW_POWER_S0 value. Accordingly, drop the ACPI_FADT_LOW_POWER_S0 check from use_acpi_alarm_quirks(). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Reviewed-by: Mario Limonciello <mario.limonciello@xxxxxxx> Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx> Link: https://lore.kernel.org/r/12054246.O9o76ZdvQC@kreacher Stable-dep-of: 83ebb7b3036d ("rtc: cmos: Disable ACPI RTC event on removal") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c index d4f6c4dd42c4..19bc1d8a5de5 100644 --- a/drivers/rtc/rtc-cmos.c +++ b/drivers/rtc/rtc-cmos.c @@ -1265,9 +1265,6 @@ static void use_acpi_alarm_quirks(void) if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) return; - if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0)) - return; - if (!is_hpet_enabled()) return;