litmus2008.git/kernel/power, branch master

PM: ACPI and APM must not be enabled at the same time

2008-01-11T17:26:47+00:00

ACPI and APM used "pm_active" to guarantee that
they would not be simultaneously active.

But pm_active was recently moved under CONFIG_PM_LEGACY,
so that without CONFIG_PM_LEGACY, pm_active became a NOP --
allowing ACPI and APM to both be simultaneously enabled.
This caused unpredictable results, including boot hangs.

Further, the code under CONFIG_PM_LEGACY is scheduled
for removal.

So replace pm_active with pm_flags.
pm_flags depends only on CONFIG_PM,
which is present for both CONFIG_APM and CONFIG_ACPI.

http://bugzilla.kernel.org/show_bug.cgi?id=9194

Signed-off-by: Len Brown 
Signed-off-by: Rafael J. Wysocki

hibernate: fix lockdep report

2007-11-15T02:45:43+00:00

Lockdep reports a circular locking dependency in the hibernate code
because
 - during system boot hibernate code (from an initcall) locks pm_mutex
   and then a sysfs buffer mutex via name_to_dev_t
 - during regular operation hibernate code locks pm_mutex under a
   sysfs buffer mutex because it's called from sysfs methods.

The deadlock can never happen because during initcall invocation nothing
can write to sysfs yet. This removes the lockdep report by marking the
initcall locking as being in a different class.

Signed-off-by: Johannes Berg 
Cc: "Rafael J. Wysocki" 
Cc: Alan Stern 
Acked-by: Peter Zijlstra 
Cc: Pavel Machek 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

trivial copy_data_pages() tidy up

2007-10-20T00:26:04+00:00

Change the loop style of copy_data_pages() to remove a duplicate condition.

Signed-off-by: Fengguang Wu 
Acked-by: Rafael J. Wysocki 
Signed-off-by: Adrian Bunk

Hibernation: Enter platform hibernation state in a consistent way

2007-10-18T21:37:20+00:00

Make hibernation_platform_enter() execute the enter-a-sleep-state sequence
instead of the mixed shutdown-with-entering-S4 thing.

Replace the shutting down of devices done by kernel_shutdown_prepare(), before
entering the ACPI S4 sleep state, with suspending them and the shutting down
of sysdevs with calling device_power_down(PMSG_SUSPEND) (just like before
entering S1 or S3, but the target state is now S4).   Also, disable the
nonboot CPUs before entering the sleep state (S4), which generally always is a
good idea.

This is known to fix the "double disk spin down during hibernation" on some
machines, eg.  HPC nx6325 (ref.  http://lkml.org/lkml/2007/8/7/316 and the
following thread).   Moreover, it has been reported to make
/sys/class/rtc/rtc0/wakealarm work correctly with hibernation for some users.
It also generally causes the hibernation state (ACPI S4) to be entered faster.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Pavel Machek 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Hibernation: Check if ACPI is enabled during restore in the right place

2007-10-18T21:37:20+00:00

The following scenario leads to total confusion of the platform firmware on
some boxes (eg. HPC nx6325):
* Hibernate with ACPI enabled
* Resume passing "acpi=off" to the boot kernel

To prevent this from happening it's necessary to check if ACPI is enabled (and
enable it if that's not the case) _right_ _after_ control has been transfered
from the boot kernel to the image kernel, before device_power_up() is called
(ie.  with interrupts disabled).   Enabling ACPI after calling
device_power_up() turns out to be insufficient.

For this reason, introduce new hibernation callback ->leave() that will be
executed before device_power_up() by the restored image kernel.   To make it
work, it also is necessary to move swsusp_suspend() from swsusp.c to disk.c
(it's name is changed to "create_image", which is more up to the point).

Signed-off-by: Rafael J. Wysocki 
Acked-by: Pavel Machek 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Hibernation: Arbitrary boot kernel support - generic code

2007-10-18T21:37:19+00:00

Add the bits needed for supporting arbitrary boot kernels to the common
hibernation code.

To support arbitrary boot kernels, make it possible to replace the 'struct
new_utsname' and the kernel version in the hibernation image header by some
architecture specific data that will be used to verify if the image is valid
and to restore the image.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Pavel Machek 
Cc: Andi Kleen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

serial: turn serial console suspend a boot rather than compile time option

2007-10-18T21:37:19+00:00

Currently, there's a CONFIG_DISABLE_CONSOLE_SUSPEND that allows one to stop
the serial console from being suspended when the rest of the machine goes
to sleep.  This is incredibly useful for debugging power management-related
things; however, having it as a compile-time option has proved to be
incredibly inconvenient for us (OLPC).  There are plenty of times that we
want serial console to not suspend, but for the most part we'd like serial
console to be suspended.

This drops CONFIG_DISABLE_CONSOLE_SUSPEND, and replaces it with a kernel
boot parameter (no_console_suspend).  By default, the serial console will
be suspended along with the rest of the system; by passing
'no_console_suspend' to the kernel during boot, serial console will remain
alive during suspend.

For now, this is pretty serial console specific; further fixes could be
applied to make this work for things like netconsole.

Signed-off-by: Andres Salomon 
Acked-by: "Rafael J. Wysocki" 
Acked-by: Pavel Machek 
Cc: Nigel Cunningham 
Cc: Russell King 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

freezer: measure freezing time

2007-10-18T21:37:19+00:00

Measure the time of the freezing of tasks, even if it doesn't fail.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Pavel Machek 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

freezer: be more verbose

2007-10-18T21:37:19+00:00

Increase the freezer's verbosity a bit, so that it's easier to read problem
reports related to it.

Signed-off-by: Rafael J. Wysocki 
Acked-by: Nigel Cunningham 
Acked-by: Pavel Machek 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

freezer: do not send signals to kernel threads

2007-10-18T21:37:19+00:00

The freezer should not send signals to kernel threads, since that may lead to
subtle problems.  In particular, commit
b74d0deb968e1f85942f17080eace015ce3c332c has changed recalc_sigpending_tsk()
so that it doesn't clear TIF_SIGPENDING.  For this reason, if the freezer
continues to send fake signals to kernel threads and the freezing of kernel
threads fails, some of them may be running with TIF_SIGPENDING set forever.

Accordingly, recalc_sigpending_tsk() shouldn't set the task's TIF_SIGPENDING
flag if TIF_FREEZE is set.

Signed-off-by: Rafael J. Wysocki 
Cc: Nigel Cunningham 
Cc: Pavel Machek 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds