On Thu, May 24, 2018 at 4:24 PM, Sebastian Andrzej Siewior
<bige...@linutronix.de> wrote:
> From: Thomas Gleixner <t...@linutronix.de>
>
> timekeeping suspend/resume calls read_persistent_clock() which takes
> rtc_lock. That results in might sleep warnings because at that point
> we run with interrupts disabled.
>
> We cannot convert rtc_lock to a raw spinlock as that would trigger
> other might sleep warnings.
>
> As a workaround we disable the might sleep warnings by setting
> system_state to SYSTEM_SUSPEND before calling sysdev_suspend() and
> restoring it to SYSTEM_RUNNING afer sysdev_resume().
>
> Signed-off-by: Thomas Gleixner <t...@linutronix.de>
> Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de>
Hmm. Don't we also need to cover suspend-to-idle?
> ---
> include/linux/kernel.h | 1 +
> kernel/power/hibernate.c | 7 +++++++
> kernel/power/suspend.c | 4 ++++
> 3 files changed, 12 insertions(+)
>
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -532,6 +532,7 @@ extern enum system_states {
> SYSTEM_HALT,
> SYSTEM_POWER_OFF,
> SYSTEM_RESTART,
> + SYSTEM_SUSPEND,
> } system_state;
>
> #define TAINT_PROPRIETARY_MODULE 0
> --- a/kernel/power/hibernate.c
> +++ b/kernel/power/hibernate.c
> @@ -287,6 +287,8 @@ static int create_image(int platform_mod
>
> local_irq_disable();
>
> + system_state = SYSTEM_SUSPEND;
> +
> error = syscore_suspend();
> if (error) {
> pr_err("Some system devices failed to power down, aborting
> hibernation\n");
> @@ -317,6 +319,7 @@ static int create_image(int platform_mod
> syscore_resume();
>
> Enable_irqs:
> + system_state = SYSTEM_RUNNING;
> local_irq_enable();
>
> Enable_cpus:
> @@ -445,6 +448,7 @@ static int resume_target_kernel(bool pla
> goto Enable_cpus;
>
> local_irq_disable();
> + system_state = SYSTEM_SUSPEND;
>
> error = syscore_suspend();
> if (error)
> @@ -478,6 +482,7 @@ static int resume_target_kernel(bool pla
> syscore_resume();
>
> Enable_irqs:
> + system_state = SYSTEM_RUNNING;
> local_irq_enable();
>
> Enable_cpus:
> @@ -563,6 +568,7 @@ int hibernation_platform_enter(void)
> goto Enable_cpus;
>
> local_irq_disable();
> + system_state = SYSTEM_SUSPEND;
> syscore_suspend();
> if (pm_wakeup_pending()) {
> error = -EAGAIN;
> @@ -575,6 +581,7 @@ int hibernation_platform_enter(void)
>
> Power_up:
> syscore_resume();
> + system_state = SYSTEM_RUNNING;
> local_irq_enable();
>
> Enable_cpus:
> --- a/kernel/power/suspend.c
> +++ b/kernel/power/suspend.c
> @@ -428,6 +428,8 @@ static int suspend_enter(suspend_state_t
> arch_suspend_disable_irqs();
> BUG_ON(!irqs_disabled());
>
> + system_state = SYSTEM_SUSPEND;
> +
> error = syscore_suspend();
> if (!error) {
> *wakeup = pm_wakeup_pending();
> @@ -443,6 +445,8 @@ static int suspend_enter(suspend_state_t
> syscore_resume();
> }
>
> + system_state = SYSTEM_RUNNING;
> +
> arch_suspend_enable_irqs();
> BUG_ON(irqs_disabled());
>
