From dcb84f335bee9c9a7781cfc5d74492dccaf066d2 Mon Sep 17 00:00:00 2001 From: Venkatesh Pallipadi Date: Mon, 19 May 2008 19:09:27 -0400 Subject: cpuidle acpi driver: fix oops on AC<->DC 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 Signed-off-by: Len Brown --- drivers/cpuidle/cpuidle.c | 40 +++++++++++++++++++++++++++++++++++----- 1 file changed, 35 insertions(+), 5 deletions(-) (limited to 'drivers/cpuidle') diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index fc555a90bb2..23554b676d6 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); -- cgit v1.2.3