ACPI and power management updates for 3.19-rc1 This time we have some more new material than we used to have during the last couple of development cycles. The most important part of it to me is the introduction of a unified interface for accessing device properties provided by platform firmware. It works with Device Trees and ACPI in a uniform way and drivers using it need not worry about where the properties come from as long as the platform firmware (either DT or ACPI) makes them available. It covers both devices and "bare" device node objects without struct device representation as that turns out to be necessary in some cases. This has been in the works for quite a few months (and development cycles) and has been approved by all of the relevant maintainers. On top of that, some drivers are switched over to the new interface (at25, leds-gpio, gpio_keys_polled) and some additional changes are made to the core GPIO subsystem to allow device drivers to manipulate GPIOs in the "canonical" way on platforms that provide GPIO information in their ACPI tables, but don't assign names to GPIO lines (in which case the driver needs to do that on the basis of what it knows about the device in question). That also has been approved by the GPIO core maintainers and the rfkill driver is now going to use it. Second is support for hardware P-states in the intel_pstate driver. It uses CPUID to detect whether or not the feature is supported by the processor in which case it will be enabled by default. However, it can be disabled entirely from the kernel command line if necessary. Next is support for a platform firmware interface based on ACPI operation regions used by the PMIC (Power Management Integrated Circuit) chips on the Intel Baytrail-T and Baytrail-T-CR platforms. That interface is used for manipulating power resources and for thermal management: sensor temperature reporting, trip point setting and so on. Also the ACPI core is now going to support the _DEP configuration information in a limited way. Basically, _DEP it supposed to reflect off-the-hierarchy dependencies between devices which may be very indirect, like when AML for one device accesses locations in an operation region handled by another device's driver (usually, the device depended on this way is a serial bus or GPIO controller). The support added this time is sufficient to make the ACPI battery driver work on Asus T100A, but it is general enough to be able to cover some other use cases in the future. Finally, we have a new cpufreq driver for the Loongson1B processor. In addition to the above, there are fixes and cleanups all over the place as usual and a traditional ACPICA update to a recent upstream release. As far as the fixes go, the ACPI LPSS (Low-power Subsystem) driver for Intel platforms should be able to handle power management of the DMA engine correctly, the cpufreq-dt driver should interact with the thermal subsystem in a better way and the ACPI backlight driver should handle some more corner cases, among other things. On top of the ACPICA update there are fixes for race conditions in the ACPICA's interrupt handling code which might lead to some random and strange looking failures on some systems. In the cleanups department the most visible part is the series of commits targeted at getting rid of the CONFIG_PM_RUNTIME configuration option. That was triggered by a discussion regarding the generic power domains code during which we realized that trying to support certain combinations of PM config options was painful and not really worth it, because nobody would use them in production anyway. For this reason, we decided to make CONFIG_PM_SLEEP select CONFIG_PM_RUNTIME and that lead to the conclusion that the latter became redundant and CONFIG_PM could be used instead of it. The material here makes that replacement in a major part of the tree, but there will be at least one more batch of that in the second part of the merge window. Specifics: - Support for retrieving device properties information from ACPI _DSD device configuration objects and a unified device properties interface for device drivers (and subsystems) on top of that. As stated above, this works with Device Trees and ACPI and allows device drivers to be written in a platform firmware (DT or ACPI) agnostic way. The at25, leds-gpio and gpio_keys_polled drivers are now going to use this new interface and the GPIO subsystem is additionally modified to allow device drivers to assign names to GPIO resources returned by ACPI _CRS objects (in case _DSD is not present or does not provide the expected data). The changes in this set are mostly from Mika Westerberg, Rafael J Wysocki, Aaron Lu, and Darren Hart with some fixes from others (Fabio Estevam, Geert Uytterhoeven). - Support for Hardware Managed Performance States (HWP) as described in Volume 3, section 14.4, of the Intel SDM in the intel_pstate driver. CPUID is used to detect whether or not the feature is supported by the processor. If supported, it will be enabled automatically unless the intel_pstate=no_hwp switch is present in the kernel command line. From Dirk Brandewie. - New Intel Broadwell-H ID for intel_pstate (Dirk Brandewie). - Support for firmware interface based on ACPI operation regions used by the PMIC chips on the Intel Baytrail-T and Baytrail-T-CR platforms for power resource control and thermal management (Aaron Lu). - Limited support for retrieving off-the-hierarchy dependencies between devices from ACPI _DEP device configuration objects and deferred probing support for the ACPI battery driver based on the _DEP information to make that driver work on Asus T100A (Lan Tianyu). - New cpufreq driver for the Loongson1B processor (Kelvin Cheung). - ACPICA update to upstream revision 20141107 which only affects tools (Bob Moore). - Fixes for race conditions in the ACPICA's interrupt handling code and in the ACPI code related to system suspend and resume (Lv Zheng and Rafael J Wysocki). - ACPI core fix for an RCU-related issue in the ioremap() regions management code that slowed down significantly after CPUs had been allowed to enter idle states even if they'd had RCU callbakcs queued and triggered some problems in certain proprietary graphics driver (and elsewhere). The fix replaces synchronize_rcu() in that code with synchronize_rcu_expedited() which makes the issue go away. From Konstantin Khlebnikov. - ACPI LPSS (Low-Power Subsystem) driver fix to handle power management of the DMA engine included into the LPSS correctly. The problem is that the DMA engine doesn't have ACPI PM support of its own and it simply is turned off when the last LPSS device having ACPI PM support goes into D3cold. To work around that, the PM domain used by the ACPI LPSS driver is redesigned so at least one device with ACPI PM support will be on as long as the DMA engine is in use. From Andy Shevchenko. - ACPI backlight driver fix to avoid using it on "Win8-compatible" systems where it doesn't work and where it was used by default by mistake (Aaron Lu). - Assorted minor ACPI core fixes and cleanups from Tomasz Nowicki, Sudeep Holla, Huang Rui, Hanjun Guo, Fabian Frederick, and Ashwin Chaugule (mostly related to the upcoming ARM64 support). - Intel RAPL (Running Average Power Limit) power capping driver fixes and improvements including new processor IDs (Jacob Pan). - Generic power domains modification to power up domains after attaching devices to them to meet the expectations of device drivers and bus types assuming devices to be accessible at probe time (Ulf Hansson). - Preliminary support for controlling device clocks from the generic power domains core code and modifications of the ARM/shmobile platform to use that feature (Ulf Hansson). - Assorted minor fixes and cleanups of the generic power domains core code (Ulf Hansson, Geert Uytterhoeven). - Assorted minor fixes and cleanups of the device clocks control code in the PM core (Geert Uytterhoeven, Grygorii Strashko). - Consolidation of device power management Kconfig options by making CONFIG_PM_SLEEP select CONFIG_PM_RUNTIME and removing the latter which is now redundant (Rafael J Wysocki and Kevin Hilman). That is the first batch of the changes needed for this purpose. - Core device runtime power management support code cleanup related to the execution of callbacks (Andrzej Hajda). - cpuidle ARM support improvements (Lorenzo Pieralisi). - cpuidle cleanup related to the CPUIDLE_FLAG_TIME_VALID flag and a new MAINTAINERS entry for ARM Exynos cpuidle (Daniel Lezcano and Bartlomiej Zolnierkiewicz). - New cpufreq driver callback (->ready) to be executed when the cpufreq core is ready to use a given policy object and cpufreq-dt driver modification to use that callback for cooling device registration (Viresh Kumar). - cpufreq core fixes and cleanups (Viresh Kumar, Vince Hsu, James Geboski, Tomeu Vizoso). - Assorted fixes and cleanups in the cpufreq-pcc, intel_pstate, cpufreq-dt, pxa2xx cpufreq drivers (Lenny Szubowicz, Ethan Zhao, Stefan Wahren, Petr Cvek). - OPP (Operating Performance Points) framework modification to allow OPPs to be removed too and update of a few cpufreq drivers (cpufreq-dt, exynos5440, imx6q, cpufreq) to remove OPPs (added during initialization) on driver removal (Viresh Kumar). - Hibernation core fixes and cleanups (Tina Ruchandani and Markus Elfring). - PM Kconfig fix related to CPU power management (Pankaj Dubey). - cpupower tool fix (Prarit Bhargava). /