From: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx> cpuidle and acpi driver interaction bug with the way cpuidle_register_driver() is called. Due to this bug, there will be oops on AC<->DC on some systems, where they support C-states in one DC and not in AC. The current code does ON BOOT: Look at CST and other C-state info to see whether more than C1 is supported. If it is, then acpi processor_idle does a cpuidle_register_driver() call, which internally enables the device. ON CST change notification (AC<->DC) and on suspend-resume: acpi driver temporarily disables device, updates the device with any new C-states, and reenables the device. The problem is is on boot, there are no C2, C3 states supported and we skip the register. Later on AC<->DC, we may get a CST notification and we try to reevaluate CST and enabled the device, without actually registering it. This causes breakage as we try to create /sys fs sub directory, without the parent directory which is created at register time. Thanks to Sanjeev for reporting the problem here. http://bugzilla.kernel.org/show_bug.cgi?id=10394 Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx> Signed-off-by: Len Brown <len.brown@xxxxxxxxx> --- drivers/acpi/processor_idle.c | 13 +++++++------ drivers/cpuidle/cpuidle.c | 40 +++++++++++++++++++++++++++++++++++----- include/linux/cpuidle.h | 1 + 3 files changed, 43 insertions(+), 11 deletions(-) diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 2dd2c1f..556ee15 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -1669,6 +1669,7 @@ static int acpi_processor_setup_cpuidle(struct acpi_processor *pr) return -EINVAL; } + dev->cpu = pr->id; for (i = 0; i < CPUIDLE_STATE_MAX; i++) { dev->states[i].name[0] = '\0'; dev->states[i].desc[0] = '\0'; @@ -1738,7 +1739,7 @@ static int acpi_processor_setup_cpuidle(struct acpi_processor *pr) int acpi_processor_cst_has_changed(struct acpi_processor *pr) { - int ret; + int ret = 0; if (boot_option_idle_override) return 0; @@ -1756,8 +1757,10 @@ int acpi_processor_cst_has_changed(struct acpi_processor *pr) cpuidle_pause_and_lock(); cpuidle_disable_device(&pr->power.dev); acpi_processor_get_power_info(pr); - acpi_processor_setup_cpuidle(pr); - ret = cpuidle_enable_device(&pr->power.dev); + if (pr->flags.power) { + acpi_processor_setup_cpuidle(pr); + ret = cpuidle_enable_device(&pr->power.dev); + } cpuidle_resume_and_unlock(); return ret; @@ -1813,7 +1816,6 @@ int __cpuinit acpi_processor_power_init(struct acpi_processor *pr, if (pr->flags.power) { #ifdef CONFIG_CPU_IDLE acpi_processor_setup_cpuidle(pr); - pr->power.dev.cpu = pr->id; if (cpuidle_register_device(&pr->power.dev)) return -EIO; #endif @@ -1850,8 +1852,7 @@ int acpi_processor_power_exit(struct acpi_processor *pr, return 0; #ifdef CONFIG_CPU_IDLE - if (pr->flags.power) - cpuidle_unregister_device(&pr->power.dev); + cpuidle_unregister_device(&pr->power.dev); #endif pr->flags.power_setup_done = 0; diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index fc555a9..23554b6 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -38,6 +38,8 @@ static void cpuidle_kick_cpus(void) static void cpuidle_kick_cpus(void) {} #endif +static int __cpuidle_register_device(struct cpuidle_device *dev); + /** * cpuidle_idle_call - the main idle loop * @@ -138,6 +140,12 @@ int cpuidle_enable_device(struct cpuidle_device *dev) if (!dev->state_count) return -EINVAL; + if (dev->registered == 0) { + ret = __cpuidle_register_device(dev); + if (ret) + return ret; + } + if ((ret = cpuidle_add_state_sysfs(dev))) return ret; @@ -232,10 +240,13 @@ static void poll_idle_init(struct cpuidle_device *dev) {} #endif /* CONFIG_ARCH_HAS_CPU_RELAX */ /** - * cpuidle_register_device - registers a CPU's idle PM feature + * __cpuidle_register_device - internal register function called before register + * and enable routines * @dev: the cpu + * + * cpuidle_lock mutex must be held before this is called */ -int cpuidle_register_device(struct cpuidle_device *dev) +static int __cpuidle_register_device(struct cpuidle_device *dev) { int ret; struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu); @@ -247,18 +258,34 @@ int cpuidle_register_device(struct cpuidle_device *dev) init_completion(&dev->kobj_unregister); - mutex_lock(&cpuidle_lock); - poll_idle_init(dev); per_cpu(cpuidle_devices, dev->cpu) = dev; list_add(&dev->device_list, &cpuidle_detected_devices); if ((ret = cpuidle_add_sysfs(sys_dev))) { - mutex_unlock(&cpuidle_lock); module_put(cpuidle_curr_driver->owner); return ret; } + dev->registered = 1; + return 0; +} + +/** + * cpuidle_register_device - registers a CPU's idle PM feature + * @dev: the cpu + */ +int cpuidle_register_device(struct cpuidle_device *dev) +{ + int ret; + + mutex_lock(&cpuidle_lock); + + if ((ret = __cpuidle_register_device(dev))) { + mutex_unlock(&cpuidle_lock); + return ret; + } + cpuidle_enable_device(dev); cpuidle_install_idle_handler(); @@ -278,6 +305,9 @@ void cpuidle_unregister_device(struct cpuidle_device *dev) { struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu); + if (dev->registered == 0) + return; + cpuidle_pause_and_lock(); cpuidle_disable_device(dev); diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index 51e6b1e..dcf77fa 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -82,6 +82,7 @@ struct cpuidle_state_kobj { }; struct cpuidle_device { + unsigned int registered:1; unsigned int enabled:1; unsigned int cpu; -- 1.5.6.rc2.23.gea81e -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
