Pull one more batch of power management and ACPI updates from Rafael Wysocki:
"These are mostly fixes on top of the previously merged recent PM and
ACPI material.
First, one commit that broke the ACPI LPSS (Low-Power Subsystem)
driver on a Dell box is reverted and there are two stable-candidate
fixes for that driver. Another fix cleans up two recently added ACPI
EC messages that look odd and the printk level of a noisy debug
message in the core ACPI resources handling code is reduced.
In addition to that we have two stable-candidate fixes for the s3c
cpufreq driver, two cpuidle powernv driver updates related to Device
Trees and a PNP subsystem cleanup that will allow us to get rid of
some old ugliness going forward. Also there is a new blacklist entry
for the ACPI backlight code.
Specifics:
- Revert a recent ACPI LPSS driver commit that prevented the touchpad
driver from loading on Dell XPS13 (Jarkko Nikula).
- Make the ACPI LPSS driver disable the I2C controllers and deassert
SPI host controllers resets at startup on Intel BayTrail and
Braswell SoCs in case they have been left in wrong states by the
platform firmware which then may casuse fatal controller driver
failures during resume from hibernation (Mika Westerberg).
- Make two recently added ACPI EC messages look better (Scot Doyle).
- Reduce the printk level of a recently added debug message related
to ACPI resources that may become noisy in some cases (Rafael J
Wysocki).
- Add a new ACPI backlight blacklist entry for Samsung Series 9
(900X3C/900X3D/900X3E/900X4C/900X4D) laptops where the native
backlight interface doesn't work while the ACPI based one does
(Jens Reyer).
- Make the PNP sybsystem's core code use __request_region() followed
by __release_region() instead of __check_region() which then will
allow us to get rid of the latter as it has no more users (Jakub
Sitnicki).
- Fix a build breakage and an issue with two __init functions that
may be called after initialization in the s3c cpufreq driver (Arnd
Bergmann).
- Make the powernv cpuidle driver read target_residency values for
idle states from a Device Tree (as we have the suitable DT bindings
for that now) and improve the parsing of the powermgmt DT node in
that driver (Preeti U Murthy)"
* tag 'pm+acpi-3.20-rc1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpuidle: powernv: Avoid endianness conversions while parsing DT
cpufreq: s3c: remove last use of resume_clocks callback
cpufreq: s3c: remove incorrect __init annotations
ACPI / LPSS: Deassert resets for SPI host controllers on Braswell
ACPI / LPSS: Always disable I2C host controllers
ACPI / resources: Change pr_info() to pr_debug() for debug information
ACPI / video: Disable native backlight on Samsung Series 9 laptops
cpuidle: powernv: Read target_residency value of idle states from DT if available
Revert "ACPI / LPSS: Remove non-existing clock control from Intel Lynxpoint I2C"
ACPI / EC: Remove non-standard log emphasis
PNP: Switch from __check_region() to __request_region()
Pull clock framework updates from Mike Turquette:
"The clock framework changes contain the usual driver additions,
enhancements and fixes mostly for ARM32, ARM64, MIPS and Power-based
devices.
Additionally the framework core underwent a bit of surgery with two
major changes:
- The boundary between the clock core and clock providers (e.g clock
drivers) is now more well defined with dedicated provider helper
functions. struct clk no longer maps 1:1 with the hardware clock
but is a true per-user cookie which helps us tracker users of
hardware clocks and debug bad behavior.
- The addition of rate constraints for clocks. Rate ranges are now
supported which are analogous to the voltage ranges in the
regulator framework.
Unfortunately these changes to the core created some breakeage. We
think we fixed it all up but for this reason there are lots of last
minute commits trying to undo the damage"
* tag 'clk-for-linus-3.20' of git://git.linaro.org/people/mike.turquette/linux: (113 commits)
clk: Only recalculate the rate if needed
Revert "clk: mxs: Fix invalid 32-bit access to frac registers"
clk: qoriq: Add support for the platform PLL
powerpc/corenet: Enable CLK_QORIQ
clk: Replace explicit clk assignment with __clk_hw_set_clk
clk: Add __clk_hw_set_clk helper function
clk: Don't dereference parent clock if is NULL
MIPS: Alchemy: Remove bogus args from alchemy_clk_fgcs_detr
clkdev: Always allocate a struct clk and call __clk_get() w/ CCF
clk: shmobile: div6: Avoid division by zero in .round_rate()
clk: mxs: Fix invalid 32-bit access to frac registers
clk: omap: compile legacy omap3 clocks conditionally
clkdev: Export clk_register_clkdev
clk: Add rate constraints to clocks
clk: remove clk-private.h
pci: xgene: do not use clk-private.h
arm: omap2+ remove dead clock code
clk: Make clk API return per-user struct clk instances
clk: tegra: Define PLLD_DSI and remove dsia(b)_mux
clk: tegra: Add support for the Tegra132 CAR IP block
...
* pnp:
PNP: Switch from __check_region() to __request_region()
* pm-cpuidle:
cpuidle: powernv: Avoid endianness conversions while parsing DT
cpuidle: powernv: Read target_residency value of idle states from DT if available
* pm-cpufreq:
cpufreq: s3c: remove last use of resume_clocks callback
cpufreq: s3c: remove incorrect __init annotations
Pull more thermal managament updates from Zhang Rui:
"Specifics:
- Exynos thermal driver refactoring. Several cleanups, code
optimization, unused symbols removal, and unused feature removal in
Exynos thermal driver. Thanks Lukasz for this effort.
- Exynos thermal driver support to OF thermal. After the code
refactoring, the driver earned the support to OF thermal. Chip
thermal data were moved from driver code to DTS, reducing the code
footprint. Thanks Lukasz for this.
- After receiving the OF thermal support, the exynos thermal driver
now must allow modular build. Thanks Arnd for detecting, reporting
and fixing this.
- Exynos thermal driver support to Exynos 7 SoC. Thanks Abhilash for
this.
- Accurate temperature reporting on Rockchip thermal driver, thanks
to Caesar.
- Fix on how OF thermal enables its zones, thanks Lukasz for fixing.
- Fixes in OF thermal examples under Documentation/. Thanks Srinivas
for fixing"
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/evalenti/linux-soc-thermal:
thermal: exynos: Add TMU support for Exynos7 SoC
dts: Documentation: Add documentation for Exynos7 SoC thermal bindings
cpufreq: exynos: allow modular build
thermal: Fix examples in DT documentation
thermal: exynos: Correct sanity check at exynos_report_trigger() function
thermal: Kconfig: Remove config for not used EXYNOS_THERMAL_CORE
thermal: exynos: Remove exynos_tmu_data.c file
thermal: rockchip: make temperature reporting much more accurate
thermal: exynos: Remove exynos_thermal_common.[c|h] files
thermal: samsung: core: Exynos TMU rework to use device tree for configuration
dts: Documentation: Update exynos-thermal.txt example for Exynos5440
dts: Documentation: Extending documentation entry for exynos-thermal
cpufreq: exynos: Use device tree to determine if cpufreq cooling should be registered
thermal: exynos: Modify exynos thermal code to use device tree for cpu cooling configuration
thermal: exynos: Provide thermal_exynos.h file to be included in device tree files
thermal: exynos: cosmetic: Correct comment format
thermal: of: Enable thermal_zoneX when sensor is correctly added
Commit 32726d2d55 ("ARM: SAMSUNG: Remove legacy clock code")
already removed the callback pointer, but there was one remaining
user:
drivers/cpufreq/s3c24xx-cpufreq.c: In function 's3c_cpufreq_resume_clocks':
drivers/cpufreq/s3c24xx-cpufreq.c:149:14: error: 'struct s3c_cpufreq_info' has no member named 'resume_clocks'
cpu_cur.info->resume_clocks();
^
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 32726d2d55 ("ARM: SAMSUNG: Remove legacy clock code")
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 3.17+ <stable@vger.kernel.org> # v3.17+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The two functions s3c2416_cpufreq_driver_init and s3c_cpufreq_register
are marked init but are called from a context that might be run after
the __init sections are discarded, as the compiler points out:
WARNING: vmlinux.o(.data+0x1ad9dc): Section mismatch in reference from the variable s3c2416_cpufreq_driver to the function .init.text:s3c2416_cpufreq_driver_init()
WARNING: drivers/built-in.o(.text+0x35b5dc): Section mismatch in reference from the function s3c2410a_cpufreq_add() to the function .init.text:s3c_cpufreq_register()
This removes the __init markings.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
On Dell Latitude C600 laptop with Pentium 3 850MHz processor, the
speedstep-smi driver sometimes loads and sometimes doesn't load with
"change to state X failed" message.
The hardware sometimes refuses to change frequency and in this case, we
need to retry later. I found out that we need to enable interrupts while
waiting. When we enable interrupts, the hardware blockage that prevents
frequency transition resolves and the transition is possible. With
disabled interrupts, the blockage doesn't resolve (no matter how long do
we wait). The exact reasons for this hardware behavior are unknown.
This patch enables interrupts in the function speedstep_set_state that can
be called with disabled interrupts. However, this function is called with
disabled interrupts only from speedstep_get_freqs, so it shouldn't cause
any problem.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com
Cc: All applicable <stable@vger.kernel.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Pull ACPI and power management updates from Rafael Wysocki:
"We have a few new features this time, including a new SFI-based
cpufreq driver, a new devfreq driver for Tegra Activity Monitor, a new
devfreq class for providing its governors with raw utilization data
and a new ACPI driver for AMD SoCs.
Still, the majority of changes here are reworks of existing code to
make it more straightforward or to prepare it for implementing new
features on top of it. The primary example is the rework of ACPI
resources handling from Jiang Liu, Thomas Gleixner and Lv Zheng with
support for IOAPIC hotplug implemented on top of it, but there is
quite a number of changes of this kind in the cpufreq core, ACPICA,
ACPI EC driver, ACPI processor driver and the generic power domains
core code too.
The most active developer is Viresh Kumar with his cpufreq changes.
Specifics:
- Rework of the core ACPI resources parsing code to fix issues in it
and make using resource offsets more convenient and consolidation
of some resource-handing code in a couple of places that have grown
analagous data structures and code to cover the the same gap in the
core (Jiang Liu, Thomas Gleixner, Lv Zheng).
- ACPI-based IOAPIC hotplug support on top of the resources handling
rework (Jiang Liu, Yinghai Lu).
- ACPICA update to upstream release 20150204 including an interrupt
handling rework that allows drivers to install raw handlers for
ACPI GPEs which then become entirely responsible for the given GPE
and the ACPICA core code won't touch it (Lv Zheng, David E Box,
Octavian Purdila).
- ACPI EC driver rework to fix several concurrency issues and other
problems related to events handling on top of the ACPICA's new
support for raw GPE handlers (Lv Zheng).
- New ACPI driver for AMD SoCs analogous to the LPSS (Low-Power
Subsystem) driver for Intel chips (Ken Xue).
- Two minor fixes of the ACPI LPSS driver (Heikki Krogerus, Jarkko
Nikula).
- Two new blacklist entries for machines (Samsung 730U3E/740U3E and
510R) where the native backlight interface doesn't work correctly
while the ACPI one does (Hans de Goede).
- Rework of the ACPI processor driver's handling of idle states to
make the code more straightforward and less bloated overall (Rafael
J Wysocki).
- Assorted minor fixes related to ACPI and SFI (Andreas Ruprecht,
Andy Shevchenko, Hanjun Guo, Jan Beulich, Rafael J Wysocki, Yaowei
Bai).
- PCI core power management modification to avoid resuming (some)
runtime-suspended devices during system suspend if they are in the
right states already (Rafael J Wysocki).
- New SFI-based cpufreq driver for Intel platforms using SFI
(Srinidhi Kasagar).
- cpufreq core fixes, cleanups and simplifications (Viresh Kumar,
Doug Anderson, Wolfram Sang).
- SkyLake CPU support and other updates for the intel_pstate driver
(Kristen Carlson Accardi, Srinivas Pandruvada).
- cpufreq-dt driver cleanup (Markus Elfring).
- Init fix for the ARM big.LITTLE cpuidle driver (Sudeep Holla).
- Generic power domains core code fixes and cleanups (Ulf Hansson).
- Operating Performance Points (OPP) core code cleanups and kernel
documentation update (Nishanth Menon).
- New dabugfs interface to make the list of PM QoS constraints
available to user space (Nishanth Menon).
- New devfreq driver for Tegra Activity Monitor (Tomeu Vizoso).
- New devfreq class (devfreq_event) to provide raw utilization data
to devfreq governors (Chanwoo Choi).
- Assorted minor fixes and cleanups related to power management
(Andreas Ruprecht, Krzysztof Kozlowski, Rickard Strandqvist, Pavel
Machek, Todd E Brandt, Wonhong Kwon).
- turbostat updates (Len Brown) and cpupower Makefile improvement
(Sriram Raghunathan)"
* tag 'pm+acpi-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (151 commits)
tools/power turbostat: relax dependency on APERF_MSR
tools/power turbostat: relax dependency on invariant TSC
Merge branch 'pci/host-generic' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci into acpi-resources
tools/power turbostat: decode MSR_*_PERF_LIMIT_REASONS
tools/power turbostat: relax dependency on root permission
ACPI / video: Add disable_native_backlight quirk for Samsung 510R
ACPI / PM: Remove unneeded nested #ifdef
USB / PM: Remove unneeded #ifdef and associated dead code
intel_pstate: provide option to only use intel_pstate with HWP
ACPI / EC: Add GPE reference counting debugging messages
ACPI / EC: Add query flushing support
ACPI / EC: Refine command storm prevention support
ACPI / EC: Add command flushing support.
ACPI / EC: Introduce STARTED/STOPPED flags to replace BLOCKED flag
ACPI: add AMD ACPI2Platform device support for x86 system
ACPI / table: remove duplicate NULL check for the handler of acpi_table_parse()
ACPI / EC: Update revision due to raw handler mode.
ACPI / EC: Reduce ec_poll() by referencing the last register access timestamp.
ACPI / EC: Fix several GPE handling issues by deploying ACPI_GPE_DISPATCH_RAW_HANDLER mode.
ACPICA: Events: Enable APIs to allow interrupt/polling adaptive request based GPE handling model
...
Pull SFI-based cpufreq driver for v3.20 from Len Brown.
* 'sfi' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux:
cpufreq: Add SFI based cpufreq driver support
SFI: fix compiler warnings
Allow users the option to disable the driver for any hardware
which does not support HWP.
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The cpufreq_cooling_unregister() function tests whether its argument is NULL
and then returns immediately. Thus the test around the call is not needed.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
To make code more readable and less error prone, lets create a helper macro for
iterating over all available governors.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
To make code more readable and less error prone, lets create a helper macro for
iterating over all active policies.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When cpufreq is disabled, the per-cpu variable would have been set to
NULL. Remove this unnecessary check.
[ Changelog from Saravana Kannan. ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
In __cpufreq_remove_dev_finish(), per-cpu 'cpufreq_cpu_data' needs
to be cleared before calling kobject_put(&policy->kobj) and under
cpufreq_driver_lock. Otherwise, if someone else calls cpufreq_cpu_get()
in parallel with it, they can obtain a non-NULL policy from that after
kobject_put(&policy->kobj) was executed.
Consider this case:
Thread A Thread B
cpufreq_cpu_get()
acquire cpufreq_driver_lock
read-per-cpu cpufreq_cpu_data
kobject_put(&policy->kobj);
kobject_get(&policy->kobj);
...
per_cpu(&cpufreq_cpu_data, cpu) = NULL
And this will result in a warning like this one:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 4 at include/linux/kref.h:47
kobject_get+0x41/0x50()
Modules linked in: acpi_cpufreq(+) nfsd auth_rpcgss nfs_acl
lockd grace sunrpc xfs libcrc32c sd_mod ixgbe igb mdio ahci hwmon
...
Call Trace:
[<ffffffff81661b14>] dump_stack+0x46/0x58
[<ffffffff81072b61>] warn_slowpath_common+0x81/0xa0
[<ffffffff81072c7a>] warn_slowpath_null+0x1a/0x20
[<ffffffff812e16d1>] kobject_get+0x41/0x50
[<ffffffff815262a5>] cpufreq_cpu_get+0x75/0xc0
[<ffffffff81527c3e>] cpufreq_update_policy+0x2e/0x1f0
[<ffffffff810b8cb2>] ? up+0x32/0x50
[<ffffffff81381aa9>] ? acpi_ns_get_node+0xcb/0xf2
[<ffffffff81381efd>] ? acpi_evaluate_object+0x22c/0x252
[<ffffffff813824f6>] ? acpi_get_handle+0x95/0xc0
[<ffffffff81360967>] ? acpi_has_method+0x25/0x40
[<ffffffff81391e08>] acpi_processor_ppc_has_changed+0x77/0x82
[<ffffffff81089566>] ? move_linked_works+0x66/0x90
[<ffffffff8138e8ed>] acpi_processor_notify+0x58/0xe7
[<ffffffff8137410c>] acpi_ev_notify_dispatch+0x44/0x5c
[<ffffffff8135f293>] acpi_os_execute_deferred+0x15/0x22
[<ffffffff8108c910>] process_one_work+0x160/0x410
[<ffffffff8108d05b>] worker_thread+0x11b/0x520
[<ffffffff8108cf40>] ? rescuer_thread+0x380/0x380
[<ffffffff81092421>] kthread+0xe1/0x100
[<ffffffff81092340>] ? kthread_create_on_node+0x1b0/0x1b0
[<ffffffff81669ebc>] ret_from_fork+0x7c/0xb0
[<ffffffff81092340>] ? kthread_create_on_node+0x1b0/0x1b0
---[ end trace 89e66eb9795efdf7 ]---
The actual code flow is as follows:
Thread A: Workqueue: kacpi_notify
acpi_processor_notify()
acpi_processor_ppc_has_changed()
cpufreq_update_policy()
cpufreq_cpu_get()
kobject_get()
Thread B: xenbus_thread()
xenbus_thread()
msg->u.watch.handle->callback()
handle_vcpu_hotplug_event()
vcpu_hotplug()
cpu_down()
__cpu_notify(CPU_POST_DEAD..)
cpufreq_cpu_callback()
__cpufreq_remove_dev_finish()
cpufreq_policy_put_kobj()
kobject_put()
cpufreq_cpu_get() gets the policy from per-cpu variable cpufreq_cpu_data
under cpufreq_driver_lock, and once it gets a valid policy it expects it
to not be freed until cpufreq_cpu_put() is called.
But the race happens when another thread puts the kobject first and updates
cpufreq_cpu_data before or later. And so the first thread gets a valid policy
structure and before it does kobject_get() on it, the second one has already
done kobject_put().
Fix this by setting cpufreq_cpu_data to NULL before putting the kobject and that
too under locks.
Reported-by: Ethan Zhao <ethan.zhao@oracle.com>
Reported-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 3.12+ <stable@vger.kernel.org> # 3.12+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The exynos cpufreq driver code recently gained a dependency on the
cooling code, which may be a loadable module. This breaks an ARM
allmodconfig build:
drivers/built-in.o: In function `exynos_cpufreq_probe':
:(.text+0x1748e8): undefined reference to `of_cpufreq_cooling_register'
To avoid this problem, change cpufreq Kconfig to allow the drivers
to be loadable modules as well and enforce a dependency on the
thermal module.
This change, in order to allow module builds on this cpufreq
driver, properly constructs the driver into a single module,
instead of several modules. The change also keeps the proper
platform dependency, and therefore, it wont load in platforms
that are not supposed to be loaded. The user will be able to
build the support for all platforms, or select which platforms
(s)he wants (as originally), except that now it can be a module,
instead.
Besides, it will still keep the driver only on those configs
that expect it to be on. And it won't compile/load on platforms
that it is not supposed to. It brings the config ARM_EXYNOS_CPU_FREQ_BOOST_SW
closer to this driver, so it looks better in the menuconfig.
We intentionally change ARM_EXYNOS5440_CPUFREQ to be tristate too, to
avoid future troubles.
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Kukjin Kim <kgene@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-pm@vger.kernel.org
Cc: linux-samsung-soc@vger.kernel.org
Fixes: e725d26c48 ("cpufreq: exynos: Use device tree to determine if cpufreq cooling should be registered")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
If the user has requested an override of the min_perf_pct via
sysfs, then it should be restored whenever policy is updated,
such as on resume. Take the max of whatever the user requested
and whatever the policy is.
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When thermal or other subsystem requests to change the policy,
use that irrepective of whether cpufreq policy is PERFORMANCE or
not. Without this change, when thermal subsystem passive policy wants
to reduce performance, it still runs at 100%.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Add a sysfs interface to display the total number of supported
pstates. This value is independent of whether turbo has been
enabled or disabled.
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This patch adds "turbo_pct" to the intel_pstate sysfs interface.
turbo_pct will display the percentage of the total supported
pstates that are in the turbo range. This value is independent
of whether turbo has been disabled or not.
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
With thermal subsystem rework it is necessary to tune current cpufreq code
to use cpu frequency change as a potential cooling device.
Now the cpu cooling device is registered only when proper nodes and properties
are available in device tree. Lack of them, however, will not prevent
cpufreq for normal operation.
Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
There is no possibility of any race on updating last_index, trans_table or
total_trans as these are updated only by cpufreq_stat_notifier_trans() which
will be called sequentially.
The only place where locking is still relevant is: cpufreq_stats_update(), which
updates time_in_state and last_time. This can be called by two thread in
parallel, that may result in races.
The two threads being:
- sysfs read of time_in_state
- and frequency transition that calls cpufreq_stat_notifier_trans().
Remove locking from the first case mentioned above.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Linus Torvalds
Rafael J. Wysocki
Arnd Bergmann
Mikulas Patocka
Kristen Carlson Accardi
Markus Elfring
Viresh Kumar
Michael Turquette
Srinivas Pandruvada
Lukasz Majewski