linux-toradex.git/drivers/cpuidle/cpuidle.c, branch v2.6.32.45

cpuidle: always return with interrupts enabled

2009-10-29T14:39:31+00:00

In the case where cpuidle_idle_call() returns before changing state due to
a need_resched(), it was returning with IRQs disabled.

The idle path assumes that the platform specific idle code returns with
interrupts enabled (although this too is undocumented AFAICT) and on ARM
we have a WARN_ON(!(irqs_disabled()) when returning from the idle loop, so
the user-visible effects were only a warning since interrupts were
eventually re-enabled later.

On x86, this same problem exists, but there is no WARN_ON() to detect it.
As on ARM, the interrupts are eventually re-enabled, so I'm not sure of
any actual bugs triggered by this.  It's primarily a
correctness/consistency fix.

This patch ensures IRQs are (re)enabled before returning.

Reported-by: Hemanth V 
Signed-off-by: Kevin Hilman 
Cc: Arjan van de Ven 
Cc: Len Brown 
Cc: Venkatesh Pallipadi 
Cc: Ingo Molnar 
Cc: "Rafael J. Wysocki" 
Tested-by: Martin Michlmayr 
Cc: 		[2.6.31.x]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

tracing, x86, cpuidle: Move the end point of a C state in the power tracer

2009-09-19T16:57:52+00:00

The "end of a C state" trace point currently happens before
the code runs that corrects the TSC for having stopped during idle.

The result of this is that the timestamp of the end-of-C-state event
is garbage on cpus where the TSC stops during idle.

This patch moves the end point of the C state to after the timekeeping
engine of the kernel has been corrected.

Signed-off-by: Arjan van de Ven 
Cc: Len Brown 
Cc: fweisbec@gmail.com
Cc: peterz@infradead.org
Cc: Paul Mackerras 
LKML-Reference: <20090919133533.139c2a46@infradead.org>
Signed-off-by: Ingo Molnar

regression: disable timer peek-ahead for 2.6.28

2008-11-10T00:28:42+00:00

It's showing up as regressions; disabling it very likely just papers
over an underlying issue, but time is running out for 2.6.28, lets get
back to this for 2.6.29

Fixes: #11826 and #11893

Signed-off-by: Arjan van de Ven 
Signed-off-by: Linus Torvalds

Merge branch 'v28-range-hrtimers-for-linus-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2008-10-23T17:53:02+00:00

* 'v28-range-hrtimers-for-linus-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (37 commits)
  hrtimers: add missing docbook comments to struct hrtimer
  hrtimers: simplify hrtimer_peek_ahead_timers()
  hrtimers: fix docbook comments
  DECLARE_PER_CPU needs linux/percpu.h
  hrtimers: fix typo
  rangetimers: fix the bug reported by Ingo for real
  rangetimer: fix BUG_ON reported by Ingo
  rangetimer: fix x86 build failure for the !HRTIMERS case
  select: fix alpha OSF wrapper
  select: fix alpha OSF wrapper
  hrtimer: peek at the timer queue just before going idle
  hrtimer: make the futex() system call use the per process slack value
  hrtimer: make the nanosleep() syscall use the per process slack
  hrtimer: fix signed/unsigned bug in slack estimator
  hrtimer: show the timer ranges in /proc/timer_list
  hrtimer: incorporate feedback from Peter Zijlstra
  hrtimer: add a hrtimer_start_range() function
  hrtimer: another build fix
  hrtimer: fix build bug found by Ingo
  hrtimer: make select() and poll() use the hrtimer range feature
  ...

cpuidle: upon BIOS bug, default to default_idle rather than polling

2008-10-16T23:00:08+00:00

http://bugzilla.kernel.org/show_bug.cgi?id=11345

Signed-off-by: Venkatesh Pallipadi 
Signed-off-by: Len Brown

cpuidle: use last_state which can reflect the actual state entered

2008-10-16T21:59:44+00:00

cpuidle accounts the idle time for the C-state it was trying to enter and
not to the actual state that the driver eventually entered. The driver may
select a different state than the one chosen by cpuidle due to
constraints like bus-mastering, etc.

Change the time acounting code to look at the dev->last_state after
returning from target_state->enter(). Driver can modify dev->last_state
internally, inside the enter routine to reflect the actual C-state
entered.

Signed-off-by: Venkatesh Pallipadi 
Tested-by: Kevin Hilman 
Signed-off-by: Len Brown

hrtimer: peek at the timer queue just before going idle

2008-09-11T14:17:49+00:00

As part of going idle, we already look at the time of the next timer event to determine
which C-state to select etc.

This patch adds functionality that causes the timers that are past their
soft expire time, to fire at this time, before we calculate the next wakeup
time. This functionality will thus avoid wakeups by running timers before
going idle rather than specially waking up for it.

Signed-off-by: Arjan van de Ven

ACPI/CPUIDLE: prevent setting pm_idle to NULL

2008-07-28T15:31:58+00:00

pm_idle_save resp. pm_idle_old can be NULL when the restore code in
acpi_processor_cst_has_changed() resp. cpuidle_uninstall_idle_handler()
is called. This can set pm_idle unconditinally to NULL, which causes the
kernel to panic when calling pm_idle in the x86 idle code. This was
covered by an extra check for !pm_idle in the x86 idle code, which was
removed during the x86 idle code refactoring.

Instead of restoring the pm_idle check in the x86 code prevent the
acpi/cpuidle code to set pm_idle to NULL.

Reported by: Dhaval Giani http://lkml.org/lkml/2008/7/2/309
Based on a debug patch from Ingo Molnar

Signed-off-by: Thomas Gleixner 
Signed-off-by: Linus Torvalds

smp_call_function: get rid of the unused nonatomic/retry argument

2008-06-26T09:24:35+00:00

It's never used and the comments refer to nonatomic and retry
interchangably. So get rid of it.

Acked-by: Jeremy Fitzhardinge 
Signed-off-by: Jens Axboe

cpuidle acpi driver: fix oops on AC<->DC

2008-06-11T23:13:45+00:00

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