| From: Thomas Gleixner <tglx@linutronix.de> |
| Date: Thu, 15 Jul 2010 10:29:00 +0200 |
| Subject: suspend: Prevent might sleep splats |
| |
| timekeeping suspend/resume calls read_persistant_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 temporary 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(). |
| |
| Needs to be revisited. |
| |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| |
| --- |
| 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 |
| @@ -491,6 +491,7 @@ 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 |
| @@ -286,6 +286,8 @@ static int create_image(int platform_mod |
| |
| local_irq_disable(); |
| |
| + system_state = SYSTEM_SUSPEND; |
| + |
| error = syscore_suspend(); |
| if (error) { |
| printk(KERN_ERR "PM: Some system devices failed to power down, " |
| @@ -315,6 +317,7 @@ static int create_image(int platform_mod |
| syscore_resume(); |
| |
| Enable_irqs: |
| + system_state = SYSTEM_RUNNING; |
| local_irq_enable(); |
| |
| Enable_cpus: |
| @@ -444,6 +447,7 @@ static int resume_target_kernel(bool pla |
| goto Enable_cpus; |
| |
| local_irq_disable(); |
| + system_state = SYSTEM_SUSPEND; |
| |
| error = syscore_suspend(); |
| if (error) |
| @@ -477,6 +481,7 @@ static int resume_target_kernel(bool pla |
| syscore_resume(); |
| |
| Enable_irqs: |
| + system_state = SYSTEM_RUNNING; |
| local_irq_enable(); |
| |
| Enable_cpus: |
| @@ -562,6 +567,7 @@ int hibernation_platform_enter(void) |
| goto Enable_cpus; |
| |
| local_irq_disable(); |
| + system_state = SYSTEM_SUSPEND; |
| syscore_suspend(); |
| if (pm_wakeup_pending()) { |
| error = -EAGAIN; |
| @@ -574,6 +580,7 @@ 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 |
| @@ -361,6 +361,8 @@ 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(); |
| @@ -377,6 +379,8 @@ static int suspend_enter(suspend_state_t |
| syscore_resume(); |
| } |
| |
| + system_state = SYSTEM_RUNNING; |
| + |
| arch_suspend_enable_irqs(); |
| BUG_ON(irqs_disabled()); |
| |