If cpufreq_register_notifier is called before pure initcalls,
init_cpufreq_transition_notifier_list will overwrite whatever it did,
causing notifiers to be ignored.

Print some noise to the kernel log if that happens.
Signed-off-by: NCesar Eduardo Barros <cesarb@cesarb.net>
Signed-off-by: NDave Jones <davej@codemonkey.org.uk>

Simplify this by moving the unlocking out of the error
paths into the exit path.
Signed-off-by: NDave Jones <davej@codemonkey.org.uk>

void * p   ->  void *p
no space between function parameters
removed excess whitespace
Signed-off-by: NDave Jones <davej@codemonkey.org.uk>

return is not a function.
Signed-off-by: NDave Jones <davej@redhat.com>

Signed-off-by: NDave Jones <davej@redhat.com>

Fix the following warnings:
WARNING: vmlinux.o(.text+0xfe6711): Section mismatch in reference from the function cpufreq_unregister_driver() to the variable .cpuinit.data:cpufreq_cpu_notifier
WARNING: vmlinux.o(.text+0xfe68af): Section mismatch in reference from the function cpufreq_register_driver() to the variable .cpuinit.data:cpufreq_cpu_notifier
WARNING: vmlinux.o(.exit.text+0xc4fa): Section mismatch in reference from the function cpufreq_stats_exit() to the variable .cpuinit.data:cpufreq_stat_cpu_notifier

The warnings were casued by references to unregister_hotcpu_notifier()
from normal functions or exit functions.
This is flagged by modpost as a potential error because
it does not know that for the non HOTPLUG_CPU
scenario the unregister_hotcpu_notifier() is a nop.
Silence the warning by replacing the __initdata
annotation with a __refdata annotation.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NDave Jones <davej@codemonkey.org.uk>

refactor to use gotos instead of explicit exit paths
Signed-off-by: NDave Jones <davej@redhat.com>

refactor to use gotos instead of explicit exit paths
Signed-off-by: NDave Jones <davej@redhat.com>

The cpufreq core should not take an extra kobject reference count for no
reason, and then refuse to release it.  This has been reported as
keeping machines from properly powering down all the way.
Signed-off-by: NBalaji Rao <balajirrao@gmail.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Yi Yang <yi.y.yang@intel.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Frans Pop <elendil@planet.nl>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

cpufreq support can't be built as a module. Fix the related configuration
help message.
Signed-off-by: NStefano Brivio <stefano.brivio@polimi.it>
Signed-off-by: NDave Jones <davej@redhat.com>

Eliminate cpufreq_userspace scaling_setspeed deadlock.

Luming Yu recently uncovered yet another cpufreq related deadlock.
One thread that continuously switches the governors and the other thread that
repeatedly cats the contents of cpufreq directory causes both these threads to
go into a deadlock.

Detailed examination of the deadlock showed the exact flow before the deadlock
as:

Thread 1			Thread 2
________			________
				cats files under /sys/devices/.../cpufreq/
Set governor to userspace
  Adds a new sysfs entry for
  scaling_setspeed
				cats files under /sys/devices/.../cpufreq/

Set governor to performance
  Holds cpufreq_rw_sem in write
  mode
  Sends a STOP notify to
  userspace governor
				cat /sys/devices/.../cpufreq/scaling_setspeed
				  Gets a handle on the above sysfs entry with
				  sysfs_get_active
				  Blocks while trying to get cpufreq_rw_sem
				  in read mode
  Remove a sysfs entry for
  scaling_setspeed
    Blocks on sysfs_deactivate
    while waiting for earlier
    get_active (on other thread)
    to drain

At this point both threads go into deadlock and any other thread that tries to
do anything with sysfs cpufreq will also block.

There seems to be no easy way to avoid this deadlock as long as
cpufreq_userspace adds/removes the sysfs entry under same kobject as cpufreq.
Below patch moves scaling_setspeed to cpufreq.c, keeping it always and calling
back the governor on read/write. This is the cleanest fix I could think of,
even though adding two callbacks in governor structure just for this seems
unnecessary.

Note that the change makes scaling_setspeed under /sys/.../cpufreq permanent
and returns <unsupported> when governor is not userspace.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NDave Jones <davej@redhat.com>

In freq_table.c, show_available_freqs()'s comment is oberviously wrong.
Change the comment to a new one to avoid confusion.
Signed-off-by: NFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDave Jones <davej@redhat.com>

Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDave Jones <davej@redhat.com>

The function __cpufreq_set_policy in file drivers/cpufreq/cpufreq.c
has a very obvious error:

        if (policy->min > data->min && policy->min > policy->max) {
                ret = -EINVAL;
                goto error_out;
        }

This condtion statement is wrong because it returns -EINVAL only if
policy->min is greater than policy->max (in this case,
"policy->min > data->min" is true for ever.). In fact, it should
return -EINVAL as well if policy->max is less than data->min.

The correct condition should be:

	if (policy->min > data->max || policy->max < data->min) {

The following test result testifies the above conclusion:

Before applying this patch:

[root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
2394000 1596000
[root@yangyi-dev /]# echo 1596000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
[root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
1596000
[root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
1596000
[root@yangyi-dev /]# echo "2000000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
-bash: echo: write error: Invalid argument
[root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
1596000
[root@yangyi-dev /]# echo "0" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
[root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
1596000
[root@yangyi-dev /]# echo "1595000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
[root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
1596000
[root@yangyi-dev /]#

After applying this patch:

[root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
2394000 1596000
[root@yangyi-dev /]# echo 1596000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
[root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
1596000
[root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
1596000
[root@localhost /]# echo "2000000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
-bash: echo: write error: Invalid argument
[root@localhost /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
1596000
[root@localhost /]# echo "0" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
-bash: echo: write error: Invalid argument
[root@localhost /]# echo "1595000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
-bash: echo: write error: Invalid argument
[root@localhost /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
1596000
[root@localhost /]# echo "1596000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
[root@localhost /]# echo "2394000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
[root@localhost /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
2394000
[root@localhost /]
Signed-off-by: NYi Yang <yi.y.yang@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

There is no need for kobject_unregister() anymore, thanks to Kay's
kobject cleanup changes, so replace all instances of it with
kobject_put().


Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Stop using kobject_register, as this way we can control the sending of
the uevent properly, after everything is properly initialized.

Cc: Dominik Brodowski <linux@brodo.de>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Shin <jacob.shin@amd.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

When the cpufreq driver starts up at boot time, it calls into the default
governor which might not be initialised yet.  This hurts when the
governor's worker function relies on memory that is not yet set up by its
init function.

This migrates all governors from module_init() to fs_initcall() when being
the default, as was already done in cpufreq_performance when it was the
only possible choice.  The performance governor is always initialized early
because it might be used as fallback even when not being the default.

Fixes at least one actual oops where ondemand is the default governor and
cpufreq_governor_dbs() uses the uninitialised kondemand_wq work-queue
during boot-time.
Signed-off-by: NJohannes Weiner <hannes@saeurebad.de>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Acked-by: NIngo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

cpufreq_stats_free_table() mustn't be __cpuexit since it's called by the
__cpuinit cpufreq_stat_cpu_callback().

This patch fixes the following section mismatch reported by
Chris Clayton:

WARNING: vmlinux.o(.init.text+0x143dd): Section mismatch: reference to .exit.text:cpufreq_stats_free_table (between 'cpufreq_stat_cpu_callback' and 'cpufreq_stats_init')
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Cc: Chris Clayton <chris2553@googlemail.com>
Acked-by: NDave Jones <davej@codemonkey.org.uk>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Ingo hit some BUG_ONs that were probably caused by these missing unlocks
causing an unbalance.  He couldn't reproduce the bug reliably, so it's
unknown that it's definitly fixing the problem he hit, but it's a fairly
good chance, and this fixes an obvious bug.

[ Dave: "Ingo followed up that he hit some lockdep related output with
         this applied, so it may not be right.  I'll look at it after
         xmas if no-one has it figured out before then."
  Akpm: "It looks pretty correct to me though." ]
Signed-off-by: NDave Jones <davej@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NDave Jones <davej@redhat.com>

Make cpufreq_conservative handle out-of-sync events properly

Currently, the cpufreq_conservative governor doesn't get notified when the
actual frequency the cpu is running at differs from what cpufreq thought it
was. As a result the cpu may stay at the maximum frequency after a s2ram /
resume cycle even though the system is idle.
Signed-off-by: NElias Oltmanns <eo@nebensachen.de>
Signed-off-by: NDave Jones <davej@redhat.com>

A number of different drivers incorrect access the kobject name field
directly.  This is not correct as the name might not be in the array.
Use the proper accessor function instead.

I don't see any reason to take an expensive lock in cpufreq_quick_get()
Reading policy->cur is a single atomic operation and after
the lock is dropped again the state could change any time anyways.

So don't take the lock in the first place.

This also makes this function interrupt safe which is useful
for some code of mine.
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
Signed-off-by: NDave Jones <davej@redhat.com>

* Stop referencing the callback directly from the __init and __exit
  functions of this driver, and instead explicitly call
  cpufreq_update_policy() et al. This enables the callback function
  to be marked as __cpuinit (and the notifier_block __cpuinitdata),
  thereby saving space when HOTPLUG_CPU=n. This also enables us to
  use other tricks to replace __cpuinit{data} in future.

* cpufreq_stats_free_table() is only called from __cpuinit or __exit
  marked functions, making it an ideal candidate for __cpuexit.

* Fix missing space in the module description
Signed-off-by: NSatyam Sharma <satyam@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDave Jones <davej@redhat.com>

The notifier_block is already __cpuinitdata, thereby allowing us to safely
mark the callback function as __cpuinit also, thereby saving space when
HOTPLUG_CPU=n.
Signed-off-by: NSatyam Sharma <satyam@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDave Jones <davej@redhat.com>

Cc: Adrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDave Jones <davej@redhat.com>

Depending on the transition latency of the HW for cpufreq switches, the
ondemand or conservative governor cannot be used with certain cpufreq
drivers.  Still the ondemand should be the default governor on a wide range
of systems.  This patch allows this and lets the governor fallback to the
performance governor at cpufreq driver load time, if the driver does not
support fast enough frequency switching.

Main benefit is that on e.g.  installation or other systems without
userspace support a working dynamic cpufreq support can be achieved on most
systems by simply loading the cpufreq driver.  This is especially essential
for recent x86(_64) laptop hardware which may rely on working dynamic
cpufreq OS support.
Signed-off-by: NThomas Renninger <trenn@suse.de>
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Bryan Wu <bryan.wu@analog.com>
Cc: Andi Kleen <ak@suse.de>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDave Jones <davej@redhat.com>

Signed-off-by: NThomas Renninger <trenn@suse.de>
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Bryan Wu <bryan.wu@analog.com>
Cc: Andi Kleen <ak@suse.de>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDave Jones <davej@redhat.com>

Negative side effect: needs NR_CPUs pointer array of memory in
CONFIG_HOTPLUG_CPU case.

Still needs userspace track keeping and rewriting of governors if governors
change while a CPU is not active (always the governor at CPU remove time is
restored).

Move of policy->user_policy.governor assignment is just a minor cleanup.
http://bugzilla.kernel.org/show_bug.cgi?id=8671Signed-off-by: NThomas Renninger <trenn@suse.de>
Signed-off-by: NMattia Dongili <malattia@linux.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDave Jones <davej@redhat.com>

There is a frequency scaling issue that I encountered with the performance
governor in combination with CPU hotplug.

In cpufreq.c CPU frequency is reduced to its minimum before the CPU gets
unregistered and set offline.  Does that have a particular reason?

Since the (k8-)governor does not monitor CPU frequency that setting also
applies then to the remaining CPU as well and lets the system run on the
lowest frequency although performance is chose as the policy.
Signed-off-by: NPeter Oruba <peter.oruba@amd.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDave Jones <davej@redhat.com>

sysfs is now completely out of driver/module lifetime game.  After
deletion, a sysfs node doesn't access anything outside sysfs proper,
so there's no reason to hold onto the attribute owners.  Note that
often the wrong modules were accounted for as owners leading to
accessing removed modules.

This patch kills now unnecessary attribute->owner.  Note that with
this change, userland holding a sysfs node does not prevent the
backing module from being unloaded.

For more info regarding lifetime rule cleanup, please read the
following message.

  http://article.gmane.org/gmane.linux.kernel/510293

(tweaked by Greg to not delete the field just yet, to make it easier to
merge things properly.)
Signed-off-by: NTejun Heo <htejun@gmail.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Commit 0a4b2ccc in cpufreq.git
eliminates the build warnings but does not pass on the error code of
sysfs_create_file to the function calling cpufreq_add_dev. Instead some
previous value of ret would be returned.
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NDave Jones <davej@redhat.com>

With tickless kernel and software coordination os P-states, ondemand
can look at wrong idle statistics. This can happen when ondemand sampling
is happening on CPU 0 and due to software coordination sampling also looks at
utilization of CPU 1. If CPU 1 is in tickless state at that moment, its idle
statistics will not be uptodate and CPU 0 thinks CPU 1 is idle for less
amount of time than it actually is.

This can be resolved by looking at all the busy times of CPUs, which is
accurate, even with tickless, and use that to determine idle time in a
round about way (total time - busy time).

Thanks to Arjan for originally reporting the ondemand bug on
Lenovo T61.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NDave Jones <davej@redhat.com>

Due to rounding and inexact jiffy accounting, idle_ticks can sometimes
be higher than total_ticks. Make sure those cases are handled as
zero load case.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NDave Jones <davej@redhat.com>

Userspace governor registers a frequency change notifier at init time, even
when no CPU is set to userspace governor. Make it register only when
atleast one CPU is using userspace.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: NDave Jones <davej@redhat.com>

Eliminate build warning (sysfs_create_file return value must be checked)
Signed-off-by: NThomas Renninger <trenn@suse.de>
Signed-off-by: NDave Jones <davej@redhat.com>

Since nonboot CPUs are now disabled after tasks and devices have been
frozen and the CPU hotplug infrastructure is used for this purpose, we need
special CPU hotplug notifications that will help the CPU-hotplug-aware
subsystems distinguish normal CPU hotplug events from CPU hotplug events
related to a system-wide suspend or resume operation in progress.  This
patch introduces such notifications and causes them to be used during
suspend and resume transitions.  It also changes all of the
CPU-hotplug-aware subsystems to take these notifications into consideration
(for now they are handled in the same way as the corresponding "normal"
ones).

[oleg@tv-sign.ru: cleanups]
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add a new deferrable delayed work init.  This can be used to schedule work
that are 'unimportant' when CPU is idle and can be called later, when CPU
eventually comes out of idle.

Use this init in cpufreq ondemand governor.
Signed-off-by: NVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Adds proper lines to help output of kconfig so people can find the module names.
Also fixed some broken leading spaces versus tabs.
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Signed-off-by: NDave Jones <davej@redhat.com>

Remove deprecated /proc/acpi/processor/performance write support

Writing to /proc/acpi/processor/xy/performance interferes with sysfs
cpufreq interface. Also removes buggy cpufreq_set_policy exported symbol.
Signed-off-by: NThomas Renninger <trenn@suse.de>
Signed-off-by: NDave Jones <davej@redhat.com>