On Monday, May 09, 2016 05:50:11 AM Ocean HY1 He wrote:
> The _PTS control method is defined in the section 7.4.1 of acpi 6.0
> spec. The _PTS control method is executed by the OS during the sleep
> transition process for S1, S2, S3, S4, and for orderly S5 shutdown.
> The sleeping state value (For example, 1, 2, 3, 4 or 5 for the S5
> soft-off state) is passed to the _PTS control method. This method
> is called after OSPM has notified native device drivers of the sleep
> state transition and before the OSPM has had a chance to fully
> prepare the system for a sleep state transition.
>
> The _PTS control method provides the BIOS a mechanism for performing
> some housekeeping, such as writing the sleep type value to the embedded
> controller, before entering the system sleeping state.
>
> According to section 7.5 of acpi 6.0 spec, _PTS should run after _TTS.
>
> Thus, a _PTS block notifier is added to the reboot notifier list so that
> the _PTS object will also be evaluated when the system reboot.
So I understand why it may be necessary to evaluate _PTS before entering S5,
but I'm totally unsure about reboot.
What does reboot have to do with S5?
> Signed-off-by: Ocean He <hehy1@xxxxxxxxxx>
> Signed-off-by: Nagananda Chumbalkar <nchumbalkar@xxxxxxxxxx>
> ---
> drivers/acpi/sleep.c | 27 +++++++++++++++++++++++++++
> 1 file changed, 27 insertions(+)
>
> diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
> index 2a8b596..8b290fb 100644
> --- a/drivers/acpi/sleep.c
> +++ b/drivers/acpi/sleep.c
> @@ -55,6 +55,26 @@ static struct notifier_block tts_notifier = {
> .priority = 0,
> };
>
> +static int pts_notify_reboot(struct notifier_block *this,
> + unsigned long code, void *x)
> +{
> + acpi_status status;
> +
> + status = acpi_execute_simple_method(NULL, "\\_PTS", ACPI_STATE_S5);
> + if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
> + /* It won't break anything. */
> + printk(KERN_NOTICE "Failure in evaluating _PTS object\n");
> + }
> +
> + return NOTIFY_DONE;
> +}
> +
> +static struct notifier_block pts_notifier = {
> + .notifier_call = pts_notify_reboot,
> + .next = NULL,
> + .priority = 0,
> +};
> +
> static int acpi_sleep_prepare(u32 acpi_state)
> {
> #ifdef CONFIG_ACPI_SLEEP
> @@ -896,5 +916,12 @@ int __init acpi_sleep_init(void)
> * object can also be evaluated when the system enters S5.
> */
> register_reboot_notifier(&tts_notifier);
> +
> + /*
> + * According to section 7.5 of acpi 6.0 spec, _PTS should run after
> + * _TTS when the system enters S5.
> + */
> + register_reboot_notifier(&pts_notifier);
Why do you have to add a second notifier?
Why can't _TTS and _PTS be evaluated from one notifier?
> +
> return 0;
> }
>
Thanks,
Rafael
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