acpi_video_unregister_backlight() is now only used by video_detect.c
which is part of the same acpi_video module as video.c, make
acpi_video_unregister_backlight() private to this module.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Remove the old backlight interface selection API now that all drivers
have been ported to the new API.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Port the backlight selection logic to the new backlight interface
selection API.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NAzael Avalos <coproscefalo@gmail.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Port the backlight selection logic to the new backlight interface
selection API.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Port the backlight selection logic to the new backlight interface
selection API.

This commit also removes various obsolete pr_xxx messages related to
backlight interface selection. These are obsolete because they assume
there is only a vendor or acpi backlight driver and no other choice.
Also they are not necessary, if the user wants to know which backlight
interfaces are registered a simple "ls /sys/class/backlight" suffices.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NMattia Dongili <malattia@linux.it>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Port the backlight selection logic to the new backlight interface
selection API.

This commit also removes various obsolete pr_xxx messages related to
backlight interface selection. These are obsolete because they assume
there is only a vendor or acpi backlight driver and no other choice.
Also they are not necessary, if the user wants to know which backlight
interfaces are registered a simple "ls /sys/class/backlight" suffices.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Port the backlight selection logic to the new backlight interface
selection API.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Port the backlight selection logic to the new backlight interface
selection API.

This commit also removes various obsolete pr_xxx messages related to
backlight interface selection. These are obsolete because they assume
there is only a vendor or acpi backlight driver and no other choice.
Also they are not necessary, if the user wants to know which backlight
interfaces are registered a simple "ls /sys/class/backlight" suffices.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Port the backlight selection logic to the new backlight interface
selection API.

This commit also removes various obsolete pr_xxx messages related to
backlight interface selection. These are obsolete because they assume
there is only a vendor or acpi backlight driver and no other choice.
Also they are not necessary, if the user wants to know which backlight
interfaces are registered a simple "ls /sys/class/backlight" suffices.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Port the backlight selection logic to the new backlight interface
selection API.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Port the backlight selection logic to the new backlight interface
selection API.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NJonathan Woithe <jwoithe@just42.net>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Port the backlight selection logic to the new backlight interface
selection API.

This commit also removes various obsolete pr_xxx messages related to
backlight interface selection. These are obsolete because they assume
there is only a vendor or acpi backlight driver and no other choice.
Also they are not necessary, if the user wants to know which backlight
interfaces are registered a simple "ls /sys/class/backlight" suffices.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Port the backlight selection logic to the new backlight interface
selection API.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NPali Rohár <pali.rohar@gmail.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Port the backlight selection logic to the new backlight interface
selection API.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NPali Rohár <pali.rohar@gmail.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Port the backlight selection logic to the new backlight interface
selection API.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Port the backlight selection logic to the new backlight interface
selection API.

This commit also removes various obsolete pr_xxx messages related to
backlight interface selection. These are obsolete because they assume
there is only a vendor or acpi backlight driver and no other choice.
Also they are not necessary, if the user wants to know which backlight
interfaces are registered a simple "ls /sys/class/backlight" suffices.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Port the backlight selection logic to the new backlight interface
selection API.

This commit also removes various obsolete pr_xxx messages related to
backlight interface selection. These are obsolete because they assume
there is only a vendor or acpi backlight driver and no other choice.
Also they are not necessary, if the user wants to know which backlight
interfaces are registered a simple "ls /sys/class/backlight" suffices.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Port the backlight selection logic to the new backlight interface
selection API.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Port the backlight selection logic to the new backlight interface
selection API.

This commit also removes various obsolete pr_xxx messages related to
backlight interface selection. These are obsolete because they assume
there is only a vendor or acpi backlight driver and no other choice.
Also they are not necessary, if the user wants to know which backlight
interfaces are registered a simple "ls /sys/class/backlight" suffices.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Reviewed-by: NLee, Chun-Yi <jlee@suse.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

It is possible for a native backlight driver to load while
acpi_video_register is running, which may lead to
acpi_video_unregister_backlight being called while acpi_video_register
is running and the 2 racing against eachother.

The register_count variable protects against this, but not in a thread
safe manner, this commit adds locking to make this thread safe.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

When builtin there is no guarantee in which order module_init functions
are run, so acpi_video_register() may get called from the i915 driver
(if it is also builtin) before acpi_video_init() gets called, resulting
in the dmi quirks not yet being parsed.

This commit moves the dmi_check_system() call to acpi_video_register(),
so that we can be sure the dmi quirks have always been applied before
probing.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Move the unregistering of the acpi backlight interface on registering of a
native backlight from video.c to video_detect.c where it belongs.

Note this removes support for re-registering the acpi backlight interface
when the native interface goes away. In practice this never happens and
it needlessly complicates the code.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Most of the patch is moving the dmi quirks for forcing use of the
acpi-video / the native backlight interface to video_detect.c.

What remains is a nice cleanup.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This results in a nice cleanup, as we can replace the complicated logic
from should_ignore_backlight_request() with a simple check for the type
being native.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Make acpi_video_set_dmi_backlight_type() call
acpi_video_unregister_backlight() when the new dmi quirk results in
the desired backlight interface being of a type other then
acpi_backlight_video.

This avoid the need for the second if in the following construction
which is currently found in many platform/x86 drivers:

	if (prefer_vendor_quirk)
		acpi_video_dmi_promote_vendor();

	if (!acpi_video_backlight_support())
		acpi_video_unregister_backlight()

This second if-block will be removed from the platform drivers as part
of their conversion to the new backlight interface selection API.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Currently we have 2 kernel commandline options + dmi-quirks in 3 places all
interacting (in interesting ways) to select which which backlight interface
to use. On the commandline we've acpi_backlight=[video|vendor] and
video.use_native_backlight=[0|1]. DMI quirks we have in
acpi/video-detect.c, acpi/video.c and drivers/platform/x86/*.c .

This commit is the first step to cleaning this up, replacing the 2 cmdline
options with just acpi_backlight=[video|vendor|native|none], and adds a
new API to video_detect.c to reflect this.

Follow up commits will also move other related code, like unregistering the
acpi_video backlight interface if it was registered before other drivers
which take priority over it are loaded, to video_detect.c where this
logic really belongs.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This is a preparation patch for the backlight interface selection logic
cleanup, there are 2 reasons to not always build the video_detect code
into the kernel:

1) In order for the video_detect.c to also deal with / select native
backlight interfaces on win8 systems, instead of doing this in video.c
where it does not belong, video_detect.c needs to call into the backlight
class code. Which cannot be done if it is builtin and the blacklight class
is not.

2) Currently all the platform/x86 drivers which have quirks to prefer
the vendor driver over acpi-video call acpi_video_unregister_backlight()
to remove the acpi-video backlight interface, this logic really belongs
in video_detect.c, which will cause video_detect.c to depend on symbols of
video.c and video.c already depends on video_detect.c symbols, so they
really need to be a single module.

Note that this commits make 2 changes so as to maintain 100% kernel
commandline compatibility:

1) The __setup call for the acpi_backlight= handling is moved to
   acpi/util.c as __setup may only be used by code which is alwasy builtin
2) video.c is renamed to acpi_video.c so that it can be combined with
   video_detect.c into video.ko

This commit also makes changes to drivers/platform/x86/Kconfig to ensure
that drivers which use acpi_video_backlight_support() from video_detect.c,
will not be built-in when acpi_video is not built in. This also changes
some "select" uses to "depends on" to avoid dependency loops.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

acpi_osi_is_win8 needs access to acpi_gbl_osi_data which is not exported,
so move it to osl.c. Alternatively we could export acpi_gbl_osi_data but
that seems undesirable.

This allows video_detect.c to be build as a module, besides that
acpi_osi_is_win8() is something which does not really belong in
video_detect.c in the first place.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

This allows video_detect.c to be build as a module, this is a preparation
patch for the backlight interface selection logic cleanup.

Note this commit also causes acpi_is_video_device() to always be build
indepedent of CONFIG_ACPI_VIDEO, as there is no reason to make its
building depend on CONFIG_ACPI_VIDEO.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

acpi_video_get_capabilities() is only used inside video_detect.c so make
it static. While at it also remove the prototype for the non existent
acpi_video_display_switch_support function from acpi.h
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Remove the now unused acpi_video_dmi_demote_vendor() function, this was
never a proper counter part of acpi_video_dmi_promote_vendor() since
the calls to acpi_video_dmi_promote_vendor() are not counted.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

acpi_video_dmi_demote_vendor() is going away as part of the cleanup of
the code for determinging which backlight class driver(s) to register.

The call to acpi_video_dmi_demote_vendor() was meant to undo the call to
acpi_video_dmi_promote_vendor() when the gmux device is removed, this is
questionable though since the promote call sets a flag, not a counter, so
the demote call may undo a promoto done elsewhere. Moreover in practice
this is a nop since the gmux device is never removed, and the flag is only
checked when acpi/video.ko gets loaded, so even if the user manually
removes apple-gmux the demote call is still a nop as video.ko will already
have loaded by this time.

Also note that none of the other users of acpi_video_dmi_promote_vendor()
use acpi_video_dmi_demote_vendor().

If we ever encounter a system with a gmux where the acpi-video interface
should be used, then the proper fix would be to dmi-blacklist the gmux
driver on that system.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

acpi_video_unregister() not only unregisters the acpi-video backlight
interface but also unregisters the acpi video bus event listener, causing
e.g. brightness hotkey presses to no longer generate keypress events.

The unregistering of the acpi video bus event listener usually is
undesirable, which by itself is a good reason to switch to
acpi_video_unregister_backlight().

Another problem with using acpi_video_unregister() rather then using
acpi_video_unregister_backlight() is that on systems with an intel video
opregion (most systems) and a broken_acpi_video quirk, whether or not
the acpi video bus event listener actually gets unregistered depends on
module load ordering:

Scenario a:
1) acpi/video.ko gets loaded (*), does not do acpi_video_register as there
   is an intel opregion.
2) intel.ko gets loaded, calls acpi_video_register() which registers both
   the listener and the acpi backlight interface
3) samsung-laptop.ko gets loaded, calls acpi_video_unregister() causing
   both the listener and the acpi backlight interface to unregister

Scenario b:
1) acpi/video.ko gets loaded (*), does not do acpi_video_register as there
   is an intel opregion.
2) samsung-laptop.ko gets loaded, calls acpi_video_dmi_promote_vendor(),
   calls acpi_video_unregister(), which is a nop since acpi_video_register
   has not yet been called
2) intel.ko gets loaded, calls acpi_video_register() which registers
   the listener, but does not register the acpi backlight interface due to
   the call to the preciding call to acpi_video_dmi_promote_vendor()

*) acpi/video.ko always loads first as both other modules depend on it.

So we end up with or without an acpi video bus event listener depending
on module load ordering, not good.

Switching to using acpi_video_unregister_backlight() means that independ
of ordering we will always have an acpi video bus event listener fixing
this.

Note that this commit means that systems without an intel video opregion,
and systems which were hitting scenario a wrt module load ordering, are
now getting an acpi video bus event listener while before they were not!

On some systems this may cause the brightness hotkeys to start generating
keypresses while before they were not (good), while on other systems this
may cause the brightness hotkeys to generate multiple keypress events for
a single press (not so good). Since on most systems the acpi video bus is
the canonical source for brightness events I believe that the latter case
will needs to be handled on a case by case basis by filtering out the
duplicate keypresses at the other source for them.

Cc: Corentin Chary <corentin.chary@gmail.com>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

acpi_video_unregister() not only unregisters the acpi-video backlight
interface but also unregisters the acpi video bus event listener, causing
e.g. brightness hotkey presses to no longer generate keypress events.

The unregistering of the acpi video bus event listener usually is
undesirable, which by itself is a good reason to switch to
acpi_video_unregister_backlight().

Another problem with using acpi_video_unregister() rather then using
acpi_video_unregister_backlight() is that on systems with an intel video
opregion (most systems) and a wmi_backlight_power quirk, whether or not
the acpi video bus event listener actually gets unregistered depends on
module load ordering:

Scenario a:
1) acpi/video.ko gets loaded (*), does not do acpi_video_register as there
   is an intel opregion.
2) intel.ko gets loaded, calls acpi_video_register() which registers both
   the listener and the acpi backlight interface
3) asus-wmi.ko gets loaded, calls acpi_video_unregister() causing both
   the listener and the acpi backlight interface to unregister

Scenario b:
1) acpi/video.ko gets loaded (*), does not do acpi_video_register as there
   is an intel opregion.
2) asus-wmi.ko gets loaded, calls acpi_video_dmi_promote_vendor(),
   calls acpi_video_unregister(), which is a nop since acpi_video_register
   has not yet been called
2) intel.ko gets loaded, calls acpi_video_register() which registers
   the listener, but does not register the acpi backlight interface due to
   the call to the preciding call to acpi_video_dmi_promote_vendor()

*) acpi/video.ko always loads first as both other modules depend on it.

So we end up with or without an acpi video bus event listener depending
on module load ordering, not good.

Switching to using acpi_video_unregister_backlight() means that independ
of ordering we will always have an acpi video bus event listener fixing
this.

Note that this commit means that systems without an intel video opregion,
and systems which were hitting scenario a wrt module load ordering, are
now getting an acpi video bus event listener while before they were not!

On some systems this may cause the brightness hotkeys to start generating
keypresses while before they were not (good), while on other systems this
may cause the brightness hotkeys to generate multiple keypress events for
a single press (not so good). Since on most systems the acpi video bus is
the canonical source for brightness events I believe that the latter case
will needs to be handled on a case by case basis by filtering out the
duplicate keypresses at the other source for them.

Cc: Corentin Chary <corentin.chary@gmail.com>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

acpi_video_unregister() not only unregisters the acpi-video backlight
interface but also unregisters the acpi video bus event listener, causing
e.g. brightness hotkey presses to no longer generate keypress events.

The unregistering of the acpi video bus event listener usually is
undesirable, which by itself is a good reason to switch to
acpi_video_unregister_backlight().

Another problem with using acpi_video_unregister() rather then using
acpi_video_unregister_backlight() is that on systems with an intel video
opregion (most systems) whether or not the acpi video bus event listener
actually gets unregistered depends on module load ordering:

Scenario a:
1) acpi/video.ko gets loaded (*), does not do acpi_video_register as there
   is an intel opregion.
2) intel.ko gets loaded, calls acpi_video_register() which registers both
   the listener and the acpi backlight interface
3) apple-gmux.ko gets loaded, calls acpi_video_unregister() causing both
   the listener and the acpi backlight interface to unregister

Scenario b:
1) acpi/video.ko gets loaded (*), does not do acpi_video_register as there
   is an intel opregion.
2) apple-gmux.ko gets loaded, calls acpi_video_dmi_promote_vendor(),
   calls acpi_video_unregister(), which is a nop since acpi_video_register
   has not yet been called
2) intel.ko gets loaded, calls acpi_video_register() which registers
   the listener, but does not register the acpi backlight interface due to
   the call to the preciding call to acpi_video_dmi_promote_vendor()

*) acpi/video.ko always loads first as both other modules depend on it.

So we end up with or without an acpi video bus event listener depending
on module load ordering, not good.

Switching to using acpi_video_unregister_backlight() means that independ
of ordering we will always have an acpi video bus event listener fixing
this.

Note that this commit means that systems without an intel video opregion,
and systems which were hitting scenario a wrt module load ordering, are
now getting an acpi video bus event listener while before they were not!

On some systems this may cause the brightness hotkeys to start generating
keypresses while before they were not (good), while on other systems this
may cause the brightness hotkeys to generate multiple keypress events for
a single press (not so good). Since on most systems the acpi video bus is
the canonical source for brightness events I believe that the latter case
will needs to be handled on a case by case basis by filtering out the
duplicate keypresses at the other source for them.

Cc: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NDarren Hart <dvhart@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Commit b9a5e5e1 "ACPI / init: Fix the ordering of
acpi_reserve_resources()" overlooked the fact that the memory
and/or I/O regions reserved by acpi_reserve_resources() may
conflict with those reserved by the PNP "system" driver.

If that conflict actually takes place, it causes the reservations
made by the "system" driver to fail while before commit b9a5e5e1
all reservations made by it and by acpi_reserve_resources() would be
successful.  In turn, that allows the resources that haven't been
reserved by the "system" driver to be used by others (e.g. PCI) which
sometimes leads to functional problems (up to and including boot
failures).

To fix that issue, introduce a common resource reservation routine,
acpi_reserve_region(), to be used by both acpi_reserve_resources()
and the "system" driver, that will track all resources reserved by
it and avoid making conflicting requests.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=99831
Link: http://marc.info/?t=143389402600001&r=1&w=2
Fixes: b9a5e5e1 "ACPI / init: Fix the ordering of acpi_reserve_resources()"
Reported-by: NRoland Dreier <roland@purestorage.com>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

by adding the missing MODULE_ALIAS(), cpufreq-dt
can be autoloaded by udev/systemd.
Signed-off-by: NFelipe Balbi <balbi@ti.com>
Acked-by: NNishanth Menon <nm@ti.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

The kernel may delay interrupts for a long time which can result in timers
being delayed. If this occurs the intel_pstate driver will crash with a
divide by zero error:

divide error: 0000 [#1] SMP
Modules linked in: btrfs zlib_deflate raid6_pq xor msdos ext4 mbcache jbd2 binfmt_misc arc4 md4 nls_utf8 cifs dns_resolver tcp_lp bnep bluetooth rfkill fuse dm_service_time iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi nf_conntrack_netbios_ns nf_conntrack_broadcast nf_conntrack_ftp ip6t_rpfilter ip6t_REJECT ipt_REJECT xt_conntrack ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw iptable_filter ip_tables intel_powerclamp coretemp vfat fat kvm_intel iTCO_wdt iTCO_vendor_support ipmi_devintf sr_mod kvm crct10dif_pclmul
 crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel cdc_ether lrw usbnet cdrom mii gf128mul glue_helper ablk_helper cryptd lpc_ich mfd_core pcspkr sb_edac edac_core ipmi_si ipmi_msghandler ioatdma wmi shpchp acpi_pad nfsd auth_rpcgss nfs_acl lockd uinput dm_multipath sunrpc xfs libcrc32c usb_storage sd_mod crc_t10dif crct10dif_common ixgbe mgag200 syscopyarea sysfillrect sysimgblt mdio drm_kms_helper ttm igb drm ptp pps_core dca i2c_algo_bit megaraid_sas i2c_core dm_mirror dm_region_hash dm_log dm_mod
CPU: 113 PID: 0 Comm: swapper/113 Tainted: G        W   --------------   3.10.0-229.1.2.el7.x86_64 #1
Hardware name: IBM x3950 X6 -[3837AC2]-/00FN827, BIOS -[A8E112BUS-1.00]- 08/27/2014
task: ffff880fe8abe660 ti: ffff880fe8ae4000 task.ti: ffff880fe8ae4000
RIP: 0010:[<ffffffff814a9279>]  [<ffffffff814a9279>] intel_pstate_timer_func+0x179/0x3d0
RSP: 0018:ffff883fff4e3db8  EFLAGS: 00010206
RAX: 0000000027100000 RBX: ffff883fe6965100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000010 RDI: 000000002e53632d
RBP: ffff883fff4e3e20 R08: 000e6f69a5a125c0 R09: ffff883fe84ec001
R10: 0000000000000002 R11: 0000000000000005 R12: 00000000000049f5
R13: 0000000000271000 R14: 00000000000049f5 R15: 0000000000000246
FS:  0000000000000000(0000) GS:ffff883fff4e0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7668601000 CR3: 000000000190a000 CR4: 00000000001407e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Stack:
 ffff883fff4e3e58 ffffffff81099dc1 0000000000000086 0000000000000071
 ffff883fff4f3680 0000000000000071 fbdc8a965e33afee ffffffff810b69dd
 ffff883fe84ec000 ffff883fe6965108 0000000000000100 ffffffff814a9100
Call Trace:
 <IRQ>

 [<ffffffff81099dc1>] ? run_posix_cpu_timers+0x51/0x840
 [<ffffffff810b69dd>] ? trigger_load_balance+0x5d/0x200
 [<ffffffff814a9100>] ? pid_param_set+0x130/0x130
 [<ffffffff8107df56>] call_timer_fn+0x36/0x110
 [<ffffffff814a9100>] ? pid_param_set+0x130/0x130
 [<ffffffff8107fdcf>] run_timer_softirq+0x21f/0x320
 [<ffffffff81077b2f>] __do_softirq+0xef/0x280
 [<ffffffff816156dc>] call_softirq+0x1c/0x30
 [<ffffffff81015d95>] do_softirq+0x65/0xa0
 [<ffffffff81077ec5>] irq_exit+0x115/0x120
 [<ffffffff81616355>] smp_apic_timer_interrupt+0x45/0x60
 [<ffffffff81614a1d>] apic_timer_interrupt+0x6d/0x80
 <EOI>

 [<ffffffff814a9c32>] ? cpuidle_enter_state+0x52/0xc0
 [<ffffffff814a9c28>] ? cpuidle_enter_state+0x48/0xc0
 [<ffffffff814a9d65>] cpuidle_idle_call+0xc5/0x200
 [<ffffffff8101d14e>] arch_cpu_idle+0xe/0x30
 [<ffffffff810c67c1>] cpu_startup_entry+0xf1/0x290
 [<ffffffff8104228a>] start_secondary+0x1ba/0x230
Code: 42 0f 00 45 89 e6 48 01 c2 43 8d 44 6d 00 39 d0 73 26 49 c1 e5 08 89 d2 4d 63 f4 49 63 c5 48 c1 e2 08 48 c1 e0 08 48 63 ca 48 99 <48> f7 f9 48 98 4c 0f af f0 49 c1 ee 08 8b 43 78 c1 e0 08 44 29
RIP  [<ffffffff814a9279>] intel_pstate_timer_func+0x179/0x3d0
 RSP <ffff883fff4e3db8>

The kernel values for cpudata for CPU 113 were:

struct cpudata {
  cpu = 113,
  timer = {
    entry = {
      next = 0x0,
      prev = 0xdead000000200200
    },
    expires = 8357799745,
    base = 0xffff883fe84ec001,
    function = 0xffffffff814a9100 <intel_pstate_timer_func>,
    data = 18446612406765768960,
<snip>
    i_gain = 0,
    d_gain = 0,
    deadband = 0,
    last_err = 22489
  },
  last_sample_time = {
    tv64 = 4063132438017305
  },
  prev_aperf = 287326796397463,
  prev_mperf = 251427432090198,
  sample = {
    core_pct_busy = 23081,
    aperf = 2937407,
    mperf = 3257884,
    freq = 2524484,
    time = {
      tv64 = 4063149215234118
    }
  }
}

which results in the time between samples = last_sample_time - sample.time
= 4063149215234118 - 4063132438017305 = 16777216813 which is 16.777 seconds.

The duration between reads of the APERF and MPERF registers overflowed a s32
sized integer in intel_pstate_get_scaled_busy()'s call to div_fp().  The result
is that int_tofp(duration_us) == 0, and the kernel attempts to divide by 0.

While the kernel shouldn't be delaying for a long time, it can and does
happen and the intel_pstate driver should not panic in this situation.  This
patch changes the div_fp() function to use div64_s64() to allow for "long"
division.  This will avoid the overflow condition on long delays.

[v2]: use div64_s64() in div_fp()
Signed-off-by: NPrarit Bhargava <prarit@redhat.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Each time the CPU switches its frequency, the clock nodes in
DTS are walked through to find proper clock source. This is
very time-consuming, for example, it is up to 500+ us on T4240.
Besides, switching time varies from clock to clock.
To optimize this, each input clock of CPU is buffered, so that
it can be picked up instantly when needed.

Since for each CPU each input clock is stored in a pointer
which takes 4 or 8 bytes memory and normally there are several
input clocks per CPU, that will not take much memory as well.
Signed-off-by: NTang Yuantian <Yuantian.Tang@freescale.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Signed-off-by: NShailendra Verma <shailendra.capricorn@gmail.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>