Messages in this thread Patch in this message | | | Date | Tue, 6 Jul 2021 08:07:11 -0700 | From | Keith Busch <> | Subject | Re: [EXT] Re: [PATCH] nvme: Add abrupt shutdown support |
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On Tue, Jul 06, 2021 at 08:14:45AM +0000, Shivamurthy Shastri (sshivamurthy) wrote: > > Is it the device that wants an abrupt shutdown or the platform? If the > > platform's power is running on limited back-up supply, and could inform > > the kernel's power management subsystem of this, then a driver could use > > that to determine if the quick shutdown is appropriate. > > Yes, the platform is running on limited back-up supply. In this case, abrupt shutdown > option will help to achieve shutdown with relatively low back-up requirements. > > Please let me know if you want to include the abrupt shutdown as part of > > static const struct dev_pm_ops nvme_dev_pm_ops = { > .suspend = nvme_suspend, > .....
Are you suggesting creating a new pm callback just for this? I don't think that's necessary.
I was considering just adding a bit to the pm_suspend_global_flags, something like the patch below. You just have to fill in the platform specific parts to set the flag.
--- diff --git a/include/linux/suspend.h b/include/linux/suspend.h index 8af13ba60c7e..f43c0b2313d0 100644 --- a/include/linux/suspend.h +++ b/include/linux/suspend.h @@ -210,9 +210,10 @@ extern int suspend_valid_only_mem(suspend_state_t state); extern unsigned int pm_suspend_global_flags; -#define PM_SUSPEND_FLAG_FW_SUSPEND BIT(0) -#define PM_SUSPEND_FLAG_FW_RESUME BIT(1) -#define PM_SUSPEND_FLAG_NO_PLATFORM BIT(2) +#define PM_SUSPEND_FLAG_FW_SUSPEND BIT(0) +#define PM_SUSPEND_FLAG_FW_RESUME BIT(1) +#define PM_SUSPEND_FLAG_NO_PLATFORM BIT(2) +#define PM_SUSPEND_FLAG_POWER_LOSS_IMMINENT BIT(3) static inline void pm_suspend_clear_flags(void) { @@ -234,6 +235,11 @@ static inline void pm_set_suspend_no_platform(void) pm_suspend_global_flags |= PM_SUSPEND_FLAG_NO_PLATFORM; } +static inline void pm_set_power_loss_imminent(void) +{ + pm_suspend_global_flags |= PM_SUSPEND_FLAG_POWER_LOSS_IMMINENT; +} + /** * pm_suspend_via_firmware - Check if platform firmware will suspend the system. * @@ -291,6 +297,21 @@ static inline bool pm_suspend_no_platform(void) return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_NO_PLATFORM); } +/** + * pm_power_loss_imminent - Check if platform is running on limited backup + * power source + * + * To be called during system-wide power management transitions to sleep states. + * + * Return 'true' if power loss may be imminent due to platform running on + * limited backup supply. If set during a shutdown, drivers should use any + * available shortcuts to prepare their device for abrupt power loss. + */ +static inline bool pm_power_loss_imminent(void) +{ + return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_POWER_LOSS_IMMINENT); +} + /* Suspend-to-idle state machnine. */ enum s2idle_states { S2IDLE_STATE_NONE, /* Not suspended/suspending. */ --
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