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SubjectRe: [PATCH] PM / watchdog: iTCO: stop watchdog during system suspend
On 04/01/2015 05:31 PM, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> If the target sleep state of the system is not an ACPI sleep state
> (S1, S2 or S3), the TCO watchdog needs to be stopped during system
> suspend, because it may not be possible to ping it any more after
> timekeeping has been suspended (suspend-to-idle does that for
> one example).
>
> For this reason, provide ->suspend_noirq and ->resume_noirq
> callbacks for the iTCO watchdog driver and use them to stop
> and restart the watchdog during system suspend and resume,
> respectively, if the system is not going to enter an ACPI
> sleep state (in which case the watchdog will be stopped
> by the platform firmware before the state is entered).
>
> Reported-by: Borun Fu <borun.fu@intel.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
> drivers/watchdog/iTCO_wdt.c | 51 ++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 51 insertions(+)
>
> Index: linux-pm/drivers/watchdog/iTCO_wdt.c
> ===================================================================
> --- linux-pm.orig/drivers/watchdog/iTCO_wdt.c
> +++ linux-pm/drivers/watchdog/iTCO_wdt.c
> @@ -51,6 +51,7 @@
> #define DRV_VERSION "1.11"
>
> /* Includes */
> +#include <linux/acpi.h> /* For ACPI support */
> #include <linux/module.h> /* For module specific items */
> #include <linux/moduleparam.h> /* For new moduleparam's */
> #include <linux/types.h> /* For standard types (like size_t) */
> @@ -103,6 +104,8 @@ static struct { /* this is private data
> struct platform_device *dev;
> /* the PCI-device */
> struct pci_dev *pdev;
> + /* whether or not the watchdog has been suspended */
> + bool suspended;
> } iTCO_wdt_private;
>
> /* module parameters */
> @@ -571,12 +574,60 @@ static void iTCO_wdt_shutdown(struct pla
> iTCO_wdt_stop(NULL);
> }
>
> +#ifdef CONFIG_PM_SLEEP
> +/*
> + * Suspend-to-idle requires this, because it stops the ticks and timekeeping, so
> + * the watchdog cannot be pinged while in that state. In ACPI sleep states the
> + * watchdog is stopped by the platform firmware.
> + */
> +
> +#ifdef CONFIG_ACPI
> +static inline bool need_suspend(void)
> +{
> + return acpi_target_system_state() == ACPI_STATE_S0;
> +}
> +#else
> +static inline bool need_suspend(void) { return true; }
> +#endif
> +
> +static int iTCO_wdt_suspend_noirq(struct device *dev)
> +{
> + int ret = 0;
> +
> + iTCO_wdt_private.suspended = false;
> + if (watchdog_active(&iTCO_wdt_watchdog_dev) && need_suspend()) {
> + ret = iTCO_wdt_stop(&iTCO_wdt_watchdog_dev);
> + if (!ret)
> + iTCO_wdt_private.suspended = true;
> + }
> + return ret;
> +}
> +
> +static int iTCO_wdt_resume_noirq(struct device *dev)
> +{
> + if (iTCO_wdt_private.suspended)
> + iTCO_wdt_start(&iTCO_wdt_watchdog_dev);
> +
> + return 0;
> +}
> +
> +struct dev_pm_ops iTCO_wdt_pm = {
> + .suspend_noirq = iTCO_wdt_suspend_noirq,
> + .resume_noirq = iTCO_wdt_resume_noirq,

Hi Rafael,

This only covers suspend and resume, but not any of the other
sleep operations (like SIMPLE_DEV_PM_OPS would do).
Is that intentional ?

> +};
> +
> +#define ITCO_WDT_PM_OPS &iTCO_wdt_pm

Checkpatch wants to see (&iTCO_wdt_pm).

ERROR: Macros with complex values should be enclosed in parentheses

Thanks,
Guenter



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