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Subject: Re: [PATCH] ACPI: scan: Turn off unused power resources during
 initialization
To:     "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc:     LKML <linux-kernel@vger.kernel.org>, linux-pm@vger.kernel.org,
        David Box <david.e.box@linux.intel.com>,
        linux-acpi@vger.kernel.org
References: <2527835.vZkJICojNU@kreacher>
From:   Paul Menzel <pmenzel@molgen.mpg.de>
Message-ID: <8b35de7b-072f-128c-6a3f-c7da5a1b91b8@molgen.mpg.de>
Date:   Wed, 17 Mar 2021 22:26:33 +0100
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Dear Rafael,


Am 17.03.21 um 17:49 schrieb Rafael J. Wysocki:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> It is reported that on certain platforms unused ACPI power resources
> that have not been explicitly turned off prevent the platform from
> reaching the lowest power state in suspend-to-idle which leads to
> excessive power draw.
> 
> For this reason, turn all of the unused ACPI power resources off
> at the end of the initial namespace scan for devices in analogy with
> resume from suspend-to-RAM.
> 
> Reported-by: David Box <david.e.box@linux.intel.com>

Thank you for the patch. Could you please add more details to the commit 
message, saying what device this was on, and if there were some 
error/warning messages pointing to the problem?


Kind regards,

Paul


> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>   drivers/acpi/internal.h |    1 +
>   drivers/acpi/scan.c     |    2 ++
>   drivers/acpi/sleep.h    |    1 -
>   3 files changed, 3 insertions(+), 1 deletion(-)
> 
> Index: linux-pm/drivers/acpi/internal.h
> ===================================================================
> --- linux-pm.orig/drivers/acpi/internal.h
> +++ linux-pm/drivers/acpi/internal.h
> @@ -139,6 +139,7 @@ int acpi_device_sleep_wake(struct acpi_d
>   int acpi_power_get_inferred_state(struct acpi_device *device, int *state);
>   int acpi_power_on_resources(struct acpi_device *device, int state);
>   int acpi_power_transition(struct acpi_device *device, int state);
> +void acpi_turn_off_unused_power_resources(void);
>   
>   /* --------------------------------------------------------------------------
>                                 Device Power Management
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -2360,6 +2360,8 @@ int __init acpi_scan_init(void)
>   		}
>   	}
>   
> +	acpi_turn_off_unused_power_resources();
> +
>   	acpi_scan_initialized = true;
>   
>    out:
> Index: linux-pm/drivers/acpi/sleep.h
> ===================================================================
> --- linux-pm.orig/drivers/acpi/sleep.h
> +++ linux-pm/drivers/acpi/sleep.h
> @@ -8,7 +8,6 @@ extern struct list_head acpi_wakeup_devi
>   extern struct mutex acpi_device_lock;
>   
>   extern void acpi_resume_power_resources(void);
> -extern void acpi_turn_off_unused_power_resources(void);
>   
>   static inline acpi_status acpi_set_waking_vector(u32 wakeup_address)
>   {