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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
@@ -473,6 +473,7 @@ 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
@@ -285,6 +285,8 @@ 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, "
@@ -314,6 +316,7 @@ static int create_image(int platform_mod
syscore_resume();
Enable_irqs:
+ system_state = SYSTEM_RUNNING;
local_irq_enable();
Enable_cpus:
@@ -437,6 +440,7 @@ static int resume_target_kernel(bool pla
goto Enable_cpus;
local_irq_disable();
+ system_state = SYSTEM_SUSPEND;
error = syscore_suspend();
if (error)
@@ -470,6 +474,7 @@ static int resume_target_kernel(bool pla
syscore_resume();
Enable_irqs:
+ system_state = SYSTEM_RUNNING;
local_irq_enable();
Enable_cpus:
@@ -555,6 +560,7 @@ int hibernation_platform_enter(void)
goto Enable_cpus;
local_irq_disable();
+ system_state = SYSTEM_SUSPEND;
syscore_suspend();
if (pm_wakeup_pending()) {
error = -EAGAIN;
@@ -567,6 +573,7 @@ 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
@@ -359,6 +359,8 @@ 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();
@@ -375,6 +377,8 @@ static int suspend_enter(suspend_state_t
syscore_resume();
}
+ system_state = SYSTEM_RUNNING;
+
arch_suspend_enable_irqs();
BUG_ON(irqs_disabled());
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