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author | Rafael J. Wysocki <rjw@sisk.pl> | 2011-01-08 00:29:20 +0100 |
---|---|---|
committer | Len Brown <len.brown@intel.com> | 2011-01-12 12:47:30 -0500 |
commit | d8c216cfa57e8a579f41729cbb88c97835d9ac8d (patch) | |
tree | 0085ebf22bf3a05607e512102a3dab065c5514a9 | |
parent | ddbd550d503c9cdefcd6674a0ef168d57d3f0917 (diff) | |
download | linux-stable-d8c216cfa57e8a579f41729cbb88c97835d9ac8d.tar.gz linux-stable-d8c216cfa57e8a579f41729cbb88c97835d9ac8d.tar.bz2 linux-stable-d8c216cfa57e8a579f41729cbb88c97835d9ac8d.zip |
cpuidle: Make cpuidle_enable_device() call poll_idle_init()
The following scenario is possible with the current cpuidle code and
the ACPI cpuidle driver:
(1) acpi_processor_cst_has_changed() is called,
(2) cpuidle_disable_device() is called,
(3) cpuidle_remove_state_sysfs() is called to remove the (presumably
outdated) states info from sysfs,
(3) acpi_processor_get_power_info() is called, the first entry in the
pr->power.states[] table is filled with zeros,
(4) acpi_processor_setup_cpuidle() is called and it doesn't fill the
first entry in pr->power.states[],
(5) cpuidle_enable_device() is called,
(6) __cpuidle_register_device() is _not_ called, since the device has
already been registered,
(7) Consequently, poll_idle_init() is _not_ called either,
(8) cpuidle_add_state_sysfs() is called to create the sysfs attributes
for the new states and it uses the bogus first table entry from
acpi_processor_get_power_info() for creating state0.
This problem is avoided if cpuidle_enable_device()
unconditionally calls poll_idle_init().
Reported-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
cc: stable@kernel.org
-rw-r--r-- | drivers/cpuidle/cpuidle.c | 82 |
1 files changed, 41 insertions, 41 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index a50710843378..97df791c74cb 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -154,6 +154,45 @@ void cpuidle_resume_and_unlock(void) EXPORT_SYMBOL_GPL(cpuidle_resume_and_unlock); +#ifdef CONFIG_ARCH_HAS_CPU_RELAX +static int poll_idle(struct cpuidle_device *dev, struct cpuidle_state *st) +{ + ktime_t t1, t2; + s64 diff; + int ret; + + t1 = ktime_get(); + local_irq_enable(); + while (!need_resched()) + cpu_relax(); + + t2 = ktime_get(); + diff = ktime_to_us(ktime_sub(t2, t1)); + if (diff > INT_MAX) + diff = INT_MAX; + + ret = (int) diff; + return ret; +} + +static void poll_idle_init(struct cpuidle_device *dev) +{ + struct cpuidle_state *state = &dev->states[0]; + + cpuidle_set_statedata(state, NULL); + + snprintf(state->name, CPUIDLE_NAME_LEN, "C0"); + snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE"); + state->exit_latency = 0; + state->target_residency = 0; + state->power_usage = -1; + state->flags = CPUIDLE_FLAG_POLL; + state->enter = poll_idle; +} +#else +static void poll_idle_init(struct cpuidle_device *dev) {} +#endif /* CONFIG_ARCH_HAS_CPU_RELAX */ + /** * cpuidle_enable_device - enables idle PM for a CPU * @dev: the CPU @@ -178,6 +217,8 @@ int cpuidle_enable_device(struct cpuidle_device *dev) return ret; } + poll_idle_init(dev); + if ((ret = cpuidle_add_state_sysfs(dev))) return ret; @@ -232,45 +273,6 @@ void cpuidle_disable_device(struct cpuidle_device *dev) EXPORT_SYMBOL_GPL(cpuidle_disable_device); -#ifdef CONFIG_ARCH_HAS_CPU_RELAX -static int poll_idle(struct cpuidle_device *dev, struct cpuidle_state *st) -{ - ktime_t t1, t2; - s64 diff; - int ret; - - t1 = ktime_get(); - local_irq_enable(); - while (!need_resched()) - cpu_relax(); - - t2 = ktime_get(); - diff = ktime_to_us(ktime_sub(t2, t1)); - if (diff > INT_MAX) - diff = INT_MAX; - - ret = (int) diff; - return ret; -} - -static void poll_idle_init(struct cpuidle_device *dev) -{ - struct cpuidle_state *state = &dev->states[0]; - - cpuidle_set_statedata(state, NULL); - - snprintf(state->name, CPUIDLE_NAME_LEN, "C0"); - snprintf(state->desc, CPUIDLE_DESC_LEN, "CPUIDLE CORE POLL IDLE"); - state->exit_latency = 0; - state->target_residency = 0; - state->power_usage = -1; - state->flags = CPUIDLE_FLAG_POLL; - state->enter = poll_idle; -} -#else -static void poll_idle_init(struct cpuidle_device *dev) {} -#endif /* CONFIG_ARCH_HAS_CPU_RELAX */ - /** * __cpuidle_register_device - internal register function called before register * and enable routines @@ -291,8 +293,6 @@ static int __cpuidle_register_device(struct cpuidle_device *dev) init_completion(&dev->kobj_unregister); - poll_idle_init(dev); - /* * cpuidle driver should set the dev->power_specified bit * before registering the device if the driver provides |