On Apr 3, 2015 06:04, Rafael J. Wysocki wrote:
> On Wednesday, April 01, 2015 06:21:40 PM Guenter Roeck wrote:
>> On 04/01/2015 05:31 PM, Rafael J. Wysocki wrote:
>>> From: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
>
> [cut]
>
>> 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 ?
>
> Yes, it is:
> (1) The problemm at hand is strictly specific to system suspend.
> (2) The SIMPLE_DEV_PM_OPS etc macros don't cover the _noirq callback
> variants
> (and we want to use the _noirq variants, because we want the
> watchdog to be stopped as late and restarted as early as reasonably
> possible). (3) I'm not even sure if adding runtime PM support to
> this driver would make any sense. :-)
>>
>>> +};
>>> +
>>> +#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
>
> Please find an updated patch below.
>
> Rafael
>
>
Tested-by: Borun Fu <borun...@intel.com>
Borun
> ---
> From: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
> Subject: PM / watchdog: iTCO: stop watchdog during system suspend
>
> 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...@intel.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@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, +}; +
> +#define ITCO_WDT_PM_OPS (&iTCO_wdt_pm) +#else +#define
> ITCO_WDT_PM_OPS NULL +#endif /* CONFIG_PM_SLEEP */ +
> static struct platform_driver iTCO_wdt_driver = { .probe =
> iTCO_wdt_probe, .remove = iTCO_wdt_remove, .shutdown
> =
> iTCO_wdt_shutdown, .driver = { .name = DRV_NAME, +
> .pm
> = ITCO_WDT_PM_OPS, }, };
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