linux-kernel - Re: [PATCH 7/7] PM / ACPI: Take device PM QoS flags into account

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Date:	Tue, 9 Oct 2012 20:36:15 -0700
From:	mark gross <markgross@...gnar.org>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	Linux PM list <linux-pm@...r.kernel.org>,
	ACPI Devel Mailing List <linux-acpi@...r.kernel.org>,
	Alan Stern <stern@...land.harvard.edu>,
	Huang Ying <ying.huang@...el.com>,
	Sarah Sharp <sarah.a.sharp@...ux.intel.com>,
	Lan Tianyu <tianyu.lan@...el.com>,
	Aaron Lu <aaron.lu@...el.com>, Jean Pihet <j-pihet@...com>,
	linux-pci@...r.kernel.org,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	mark gross <markgross@...gnar.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 7/7] PM / ACPI: Take device PM QoS flags into account

On Mon, Oct 08, 2012 at 10:09:26AM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> Make ACPI power management routines and PCI power management
> routines depending on ACPI take device PM QoS flags into account
> when deciding what power state to put the device into.
> 
> In particular, after this change acpi_pm_device_sleep_state() will
> not return ACPI_STATE_D3_COLD as the deepest available low-power
> state if PM_QOS_FLAG_NO_POWER_OFF is requested for the device and it
> will not require remote wakeup to work for the device in the returned
> low-power state if there is at least one PM QoS flags request for the
> device, but PM_QOS_FLAG_REMOTE_WAKEUP is not requested for it.
> 
> Accordingly, acpi_pci_set_power_state() will refuse to put the
> device into D3cold if PM_QOS_FLAG_NO_POWER_OFF is requested for it.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> Reviewed-by: Jean Pihet <j-pihet@...com>
> ---
>  drivers/acpi/sleep.c   |   21 +++++++++++++++++----
>  drivers/pci/pci-acpi.c |    8 +++++++-
>  2 files changed, 24 insertions(+), 5 deletions(-)
> 
> Index: linux/drivers/pci/pci-acpi.c
> ===================================================================
> --- linux.orig/drivers/pci/pci-acpi.c
> +++ linux/drivers/pci/pci-acpi.c
> @@ -17,6 +17,7 @@
>  
>  #include <linux/pci-acpi.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/pm_qos.h>
>  #include "pci.h"
>  
>  static DEFINE_MUTEX(pci_acpi_pm_notify_mtx);
> @@ -257,11 +258,16 @@ static int acpi_pci_set_power_state(stru
>  		return -ENODEV;
>  
>  	switch (state) {
> +	case PCI_D3cold:
> +		if (dev_pm_qos_flags(&dev->dev, PM_QOS_FLAG_NO_POWER_OFF) ==
> +				PM_QOS_FLAGS_ALL) {
> +			error = -EBUSY;
> +			break;
> +		}
>  	case PCI_D0:
>  	case PCI_D1:
>  	case PCI_D2:
>  	case PCI_D3hot:
> -	case PCI_D3cold:
>  		error = acpi_bus_set_power(handle, state_conv[state]);
>  	}
>  
> Index: linux/drivers/acpi/sleep.c
> ===================================================================
> --- linux.orig/drivers/acpi/sleep.c
> +++ linux/drivers/acpi/sleep.c
> @@ -19,6 +19,7 @@
>  #include <linux/acpi.h>
>  #include <linux/module.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/pm_qos.h>
>  
>  #include <asm/io.h>
>  
> @@ -711,6 +712,7 @@ int acpi_pm_device_sleep_state(struct de
>  	struct acpi_device *adev;
>  	char acpi_method[] = "_SxD";
>  	unsigned long long d_min, d_max;
> +	bool wakeup = false;
>  
>  	if (d_max_in < ACPI_STATE_D0 || d_max_in > ACPI_STATE_D3)
>  		return -EINVAL;
> @@ -718,6 +720,13 @@ int acpi_pm_device_sleep_state(struct de
>  		printk(KERN_DEBUG "ACPI handle has no context!\n");
>  		return -ENODEV;
>  	}
> +	if (d_max_in > ACPI_STATE_D3_HOT) {
> +		enum pm_qos_flags_status stat;
> +
> +		stat = dev_pm_qos_flags(dev, PM_QOS_FLAG_NO_POWER_OFF);
> +		if (stat == PM_QOS_FLAGS_ALL)
> +			d_max_in = ACPI_STATE_D3_HOT;
> +	}
>  
>  	acpi_method[2] = '0' + acpi_target_sleep_state;
>  	/*
> @@ -737,8 +746,14 @@ int acpi_pm_device_sleep_state(struct de
>  	 * NOTE: We rely on acpi_evaluate_integer() not clobbering the integer
>  	 * provided -- that's our fault recovery, we ignore retval.
>  	 */
> -	if (acpi_target_sleep_state > ACPI_STATE_S0)
> +	if (acpi_target_sleep_state > ACPI_STATE_S0) {
>  		acpi_evaluate_integer(handle, acpi_method, NULL, &d_min);
> +		wakeup = device_may_wakeup(dev) && adev->wakeup.flags.valid
> +			&& adev->wakeup.sleep_state >= acpi_target_sleep_state;
> +	} else if (dev_pm_qos_flags(dev, PM_QOS_FLAG_REMOTE_WAKEUP) !=
> +			PM_QOS_FLAGS_NONE) {
> +		wakeup = adev->wakeup.flags.valid;
> +	}
>  
>  	/*
>  	 * If _PRW says we can wake up the system from the target sleep state,
> @@ -747,9 +762,7 @@ int acpi_pm_device_sleep_state(struct de
>  	 * (ACPI 3.x), it should return the maximum (lowest power) D-state that
>  	 * can wake the system.  _S0W may be valid, too.
>  	 */
> -	if (acpi_target_sleep_state == ACPI_STATE_S0 ||
> -	    (device_may_wakeup(dev) && adev->wakeup.flags.valid &&
> -	     adev->wakeup.sleep_state >= acpi_target_sleep_state)) {
> +	if (wakeup) {
>  		acpi_status status;
>  
>  		acpi_method[3] = 'W';
> 
> --
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> Reviewed-by: mark gross <markgross@...gnar.org>

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