linux/drivers/cpuidle, branch v3.6

cpuidle: Prevent null pointer dereference in cpuidle_coupled_cpu_notify

2012-08-17T17:37:08Z

When a kernel is built to support multiple hardware types it's possible that CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED is set but the hardware the kernel is run on doesn't support cpuidle and therefore doesn't load a driver for it. In this case, when the system is shut down, cpuidle_coupled_cpu_notify() gets called with cpuidle_devices set to NULL. There are quite possibly other circumstances where this situation can also occur and we should check for it. Signed-off-by: Jon Medhurst Signed-off-by: Rafael J. Wysocki

cpuidle: coupled: fix sleeping while atomic in cpu notifier

2012-08-17T17:37:01Z

The cpu hotplug notifier gets called in both atomic and non-atomic contexts, it is not always safe to lock a mutex. Filter out all events except the six necessary ones, which are all sleepable, before taking the mutex. Signed-off-by: Colin Cross Reviewed-by: Srivatsa S. Bhat Signed-off-by: Rafael J. Wysocki

Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux

2012-07-26T21:28:55Z

Pull ACPI & power management update from Len Brown: "Re-write of the turbostat tool. lower overhead was necessary for measuring very large system when they are very idle. IVB support in intel_idle It's what I run on my IVB, others should be able to also:-) ACPICA core update We have found some bugs due to divergence between Linux and the upstream ACPICA base. Most of these patches are to reduce that divergence to reduce the risk of future bugs. Some cpuidle updates, mostly for non-Intel More will be coming, as they depend on this part. Some thermal management changes needed by non-ACPI systems. Some _OST (OS Status Indication) updates for hot ACPI hot-plug." * 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux: (51 commits) Thermal: Documentation update Thermal: Add Hysteresis attributes Thermal: Make Thermal trip points writeable ACPI/AC: prevent OOPS on some boxes due to missing check power_supply_register() return value check tools/power: turbostat: fix large c1% issue tools/power: turbostat v2 - re-write for efficiency ACPICA: Update to version 20120711 ACPICA: AcpiSrc: Fix some translation issues for Linux conversion ACPICA: Update header files copyrights to 2012 ACPICA: Add new ACPI table load/unload external interfaces ACPICA: Split file: tbxface.c -> tbxfload.c ACPICA: Add PCC address space to space ID decode function ACPICA: Fix some comment fields ACPICA: Table manager: deploy new firmware error/warning interfaces ACPICA: Add new interfaces for BIOS(firmware) errors and warnings ACPICA: Split exception code utilities to a new file, utexcep.c ACPI: acpi_pad: tune round_robin_time ACPICA: Update to version 20120620 ACPICA: Add support for implicit notify on multiple devices ACPICA: Update comments; no functional change ...

Merge branches 'acpi_pad', 'acpica', 'apei-bugzilla-43282', 'battery', 'cpuidle-coupled', 'cpuidle-tweaks', 'intel_idle-ivb', 'ost', 'red-hat-bz-772730', 'thermal', 'thermal-spear' and 'turbostat-v2' into release

2012-07-26T04:03:58Z

Merge branch 'pm-domains'

2012-07-18T22:03:17Z

* pm-domains: PM / Domains: Fix build warning for CONFIG_PM_RUNTIME unset PM / Domains: Replace plain integer with NULL pointer in domain.c file PM / Domains: Add missing static storage class specifier in domain.c file PM / Domains: Allow device callbacks to be added at any time PM / Domains: Add device domain data reference counter PM / Domains: Add preliminary support for cpuidle, v2 PM / Domains: Do not stop devices after restoring their states PM / Domains: Use subsystem runtime suspend/resume callbacks by default

PM / cpuidle: System resume hang fix with cpuidle

2012-07-10T19:34:49Z

On certain bios, resume hangs if cpus are allowed to enter idle states during suspend [1]. This was fixed in apci idle driver [2].But intel_idle driver does not have this fix. Thus instead of replicating the fix in both the idle drivers, or in more platform specific idle drivers if needed, the more general cpuidle infrastructure could handle this. A suspend callback in cpuidle_driver could handle this fix. But a cpuidle_driver provides only basic functionalities like platform idle state detection capability and mechanisms to support entry and exit into CPU idle states. All other cpuidle functions are found in the cpuidle generic infrastructure for good reason that all cpuidle drivers, irrepective of their platforms will support these functions. One option therefore would be to register a suspend callback in cpuidle which handles this fix. This could be called through a PM_SUSPEND_PREPARE notifier. But this is too generic a notfier for a driver to handle. Also, ideally the job of cpuidle is not to handle side effects of suspend. It should expose the interfaces which "handle cpuidle 'during' suspend" or any other operation, which the subsystems call during that respective operation. The fix demands that during suspend, no cpus should be allowed to enter deep C-states. The interface cpuidle_uninstall_idle_handler() in cpuidle ensures that. Not just that it also kicks all the cpus which are already in idle out of their idle states which was being done during cpu hotplug through a CPU_DYING_FROZEN callbacks. Now the question arises about when during suspend should cpuidle_uninstall_idle_handler() be called. Since we are dealing with drivers it seems best to call this function during dpm_suspend(). Delaying the call till dpm_suspend_noirq() does no harm, as long as it is before cpu_hotplug_begin() to avoid race conditions with cpu hotpulg operations. In dpm_suspend_noirq(), it would be wise to place this call before suspend_device_irqs() to avoid ugly interactions with the same. Ananlogously, during resume. References: [1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/674075. [2] http://marc.info/?l=linux-pm&m=133958534231884&w=2 Reported-and-tested-by: Dave Hansen Signed-off-by: Preeti U Murthy Reviewed-by: Srivatsa S. Bhat Signed-off-by: Rafael J. Wysocki

PM / Domains: Add preliminary support for cpuidle, v2

2012-07-03T17:07:42Z

On some systems there are CPU cores located in the same power domains as I/O devices. Then, power can only be removed from the domain if all I/O devices in it are not in use and the CPU core is idle. Add preliminary support for that to the generic PM domains framework. First, the platform is expected to provide a cpuidle driver with one extra state designated for use with the generic PM domains code. This state should be initially disabled and its exit_latency value should be set to whatever time is needed to bring up the CPU core itself after restoring power to it, not including the domain's power on latency. Its .enter() callback should point to a procedure that will remove power from the domain containing the CPU core at the end of the CPU power transition. The remaining characteristics of the extra cpuidle state, referred to as the "domain" cpuidle state below, (e.g. power usage, target residency) should be populated in accordance with the properties of the hardware. Next, the platform should execute genpd_attach_cpuidle() on the PM domain containing the CPU core. That will cause the generic PM domains framework to treat that domain in a special way such that: * When all devices in the domain have been suspended and it is about to be turned off, the states of the devices will be saved, but power will not be removed from the domain. Instead, the "domain" cpuidle state will be enabled so that power can be removed from the domain when the CPU core is idle and the state has been chosen as the target by the cpuidle governor. * When the first I/O device in the domain is resumed and __pm_genpd_poweron(() is called for the first time after power has been removed from the domain, the "domain" cpuidle state will be disabled to avoid subsequent surprise power removals via cpuidle. The effective exit_latency value of the "domain" cpuidle state depends on the time needed to bring up the CPU core itself after restoring power to it as well as on the power on latency of the domain containing the CPU core. Thus the "domain" cpuidle state's exit_latency has to be recomputed every time the domain's power on latency is updated, which may happen every time power is restored to the domain, if the measured power on latency is greater than the latency stored in the corresponding generic_pm_domain structure. Signed-off-by: Rafael J. Wysocki Reviewed-by: Kevin Hilman

PM / cpuidle: Add driver reference counter

2012-07-03T17:06:25Z

Add a reference counter for the cpuidle driver, so that it can't be unregistered when it is in use. Signed-off-by: Rafael J. Wysocki

cpuidle: move field disable from per-driver to per-cpu

2012-07-03T17:05:31Z

Andrew J.Schorr raises a question. When he changes the disable setting on a single CPU, it affects all the other CPUs. Basically, currently, the disable field is per-driver instead of per-cpu. All the C states of the same driver are shared by all CPU in the same machine. The patch changes the `disable' field to per-cpu, so we could set this separately for each cpu. Signed-off-by: ShuoX Liu Reported-by: Andrew J.Schorr Reviewed-by: Yanmin Zhang Signed-off-by: Andrew Morton Signed-off-by: Rafael J. Wysocki

cpuidle: coupled: add parallel barrier function

2012-06-02T04:49:36Z

Adds cpuidle_coupled_parallel_barrier, which can be used by coupled cpuidle state enter functions to handle resynchronization after determining if any cpu needs to abort. The normal use case will be: static bool abort_flag; static atomic_t abort_barrier; int arch_cpuidle_enter(struct cpuidle_device *dev, ...) { if (arch_turn_off_irq_controller()) { /* returns an error if an irq is pending and would be lost if idle continued and turned off power */ abort_flag = true; } cpuidle_coupled_parallel_barrier(dev, &abort_barrier); if (abort_flag) { /* One of the cpus didn't turn off it's irq controller */ arch_turn_on_irq_controller(); return -EINTR; } /* continue with idle */ ... } This will cause all cpus to abort idle together if one of them needs to abort. Reviewed-by: Santosh Shilimkar Tested-by: Santosh Shilimkar Reviewed-by: Kevin Hilman Tested-by: Kevin Hilman Signed-off-by: Colin Cross Signed-off-by: Len Brown