Add a new latency tolerance device PM QoS type to be use for
specifying active state (RPM_ACTIVE) memory access (DMA) latency
tolerance requirements for devices.  It may be used to prevent
hardware from choosing overly aggressive energy-saving operation
modes (causing too much latency to appear) for the whole platform.

This feature reqiures hardware support, so it only will be
available for devices having a new .set_latency_tolerance()
callback in struct dev_pm_info populated, in which case the
routine pointed to by it should implement whatever is necessary
to transfer the effective requirement value to the hardware.

Whenever the effective latency tolerance changes for the device,
its .set_latency_tolerance() callback will be executed and the
effective value will be passed to it.  If that value is negative,
which means that the list of latency tolerance requirements for
the device is empty, the callback is expected to switch the
underlying hardware latency tolerance control mechanism to an
autonomous mode if available.  If that value is PM_QOS_LATENCY_ANY,
in turn, and the hardware supports a special "no requirement"
setting, the callback is expected to use it.  That allows software
to prevent the hardware from automatically updating the device's
latency tolerance in response to its power state changes (e.g. during
transitions from D3cold to D0), which generally may be done in the
autonomous latency tolerance control mode.

If .set_latency_tolerance() is present for the device, a new
pm_qos_latency_tolerance_us attribute will be present in the
devivce's power directory in sysfs.  Then, user space can use
that attribute to specify its latency tolerance requirement for
the device, if any.  Writing "any" to it means "no requirement, but
do not let the hardware control latency tolerance" and writing
"auto" to it allows the hardware to be switched to the autonomous
mode if there are no other requirements from the kernel side in the
device's list.

This changeset includes a fix from Mika Westerberg.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Add a new field, no_constraints_value, to struct pm_qos_constraints
representing a list of PM QoS constraint requests to be returned by
pm_qos_get_value() when that list of requests is empty.

That field will be equal to default_value for all of the existing
global PM QoS classes and for the resume latency device PM QoS type,
but it will be different from default_value for the new latency
tolerance device PM QoS type introduced by the next changeset.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Let kstrtos32_from_user() do the necessary calls and checks.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

pm_qos_update_request_timeout() updates a qos and then schedules
a delayed work item to bring the qos back down to the default
after the timeout. When the work item runs, pm_qos_work_fn() will
call pm_qos_update_request() and deadlock because it tries to
cancel itself via cancel_delayed_work_sync(). Future callers of
that qos will also hang waiting to cancel the work that is
canceling itself. Let's extract the little bit of code that does
the real work of pm_qos_update_request() and call it from the
work function so that we don't deadlock.

Before ed1ac6e (PM: don't use [delayed_]work_pending()) this didn't
happen because the work function wouldn't try to cancel itself.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Reviewed-by: Tejun Heo <tj@kernel.org>
Cc: 3.9+ <stable@vger.kernel.org> # 3.9+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Adds tracepoints to pm_qos_add_request, pm_qos_update_request,
pm_qos_remove_request, and pm_qos_update_request_timeout.
It's useful for checking pm_qos_class, value, and timeout_us.

Signed-off-by: Sahara <keun-o.park@windriver.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

This patch adds tracepoints to pm_qos_update_target and
pm_qos_update_flags. It's useful for checking pm qos action,
previous value and current value.

Signed-off-by: Sahara <keun-o.park@windriver.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The valid start index for pm_qos_array is not 0, but
PM_QOS_CPU_DMA_LATENCY. There is a null_pm_qos at index 0 of
pm_qos_array.  However, null_pm_qos is not created as misc device so
that inclusion of 0 index for checking pm_qos_class especially for
file operations is not proper here.

[rjw: Changelog, a bit]
Signed-off-by: Sahara <keun-o.park@windriver.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

There's no need to test whether a (delayed) work item is pending
before queueing, flushing or cancelling it, so remove work_pending()
tests used in those cases.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

* pm-sleep:
  PM / Freezer: Fixup compile error of try_to_freeze_nowarn()
  driver core / PM: move the calling to device_pm_remove behind the calling to bus_remove_device
  PM / Hibernate: use rb_entry
  PM / sysfs: replace strict_str* with kstrto*

Replace strict_strtoul() with kstrtoul() in pm_async_store() and
pm_qos_power_write().

[rjw: Modified subject and changelog.]

Signed-off-by: Daniel Walter <sahne@0x90.at>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>