PM: QoS: Add check to make sure CPU latency is non-negative

CPU latency should never be negative, which will be incorrectly high
when converted to unsigned data type.

Commit 8d36694245f2 ("PM: QoS:

PM: QoS: Add check to make sure CPU latency is non-negative

CPU latency should never be negative, which will be incorrectly high
when converted to unsigned data type.

Commit 8d36694245f2 ("PM: QoS: Add check to make sure CPU freq is
non-negative") makes sure CPU frequency is non-negative to fix incorrect
behavior in freqency QoS.

Add an analogous check to make sure CPU latency is non-negative so as to
prevent this problem from happening in CPU latency QoS.

Signed-off-by: Clive Lin <[email protected]>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <[email protected]>

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PM: QoS: Restore support for default value on frequency QoS

Commit 8d36694245f2 ("PM: QoS: Add check to make sure CPU freq is
non-negative") makes sure CPU freq is non-negative to avoid negative
val

PM: QoS: Restore support for default value on frequency QoS

Commit 8d36694245f2 ("PM: QoS: Add check to make sure CPU freq is
non-negative") makes sure CPU freq is non-negative to avoid negative
value converting to unsigned data type. However, when the value is
PM_QOS_DEFAULT_VALUE, pm_qos_update_target specifically uses
c->default_value which is set to FREQ_QOS_MIN/MAX_DEFAULT_VALUE when
cpufreq_policy_alloc is executed, for this case handling.

Adding check for PM_QOS_DEFAULT_VALUE to let default setting work will
fix this problem.

Fixes: 8d36694245f2 ("PM: QoS: Add check to make sure CPU freq is non-negative")
Link: https://lore.kernel.org/lkml/[email protected]/
Link: https://lore.kernel.org/lkml/[email protected]/
Link: https://lore.kernel.org/lkml/CAJZ5v0gxNOWhC58PHeUhW_tgf6d1fGJVZ1x91zkDdht11yUv-A@mail.gmail.com/
Signed-off-by: Chungkai Yang <[email protected]>
Cc: 6.0+ <[email protected]> # 6.0+
Signed-off-by: Rafael J. Wysocki <[email protected]>

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PM: QoS: Add check to make sure CPU freq is non-negative

CPU frequency should never be negative.

If some client driver calls freq_qos_update_request with a
negative value which will be very high in

PM: QoS: Add check to make sure CPU freq is non-negative

CPU frequency should never be negative.

If some client driver calls freq_qos_update_request with a
negative value which will be very high in absolute terms,
then frequency QoS sets max CPU freq at fmax as it considers
it's absolute value but it will add plist node with negative
priority.

plist node has priority from INT_MIN (highest) to INT_MAX(lowest).
Once priority is set as negative, another client will not be able
to reduce CPU frequency.

Adding check to make sure CPU freq is non-negative will fix
this problem.

Signed-off-by: Shivnandan Kumar <[email protected]>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <[email protected]>

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treewide: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through mar

treewide: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <[email protected]>

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PM: QoS: annotate data races in pm_qos_*_value()

The target_value field in struct pm_qos_constraints is used for
lockless access to the effective constraint value of a given QoS
list, so the readers

PM: QoS: annotate data races in pm_qos_*_value()

The target_value field in struct pm_qos_constraints is used for
lockless access to the effective constraint value of a given QoS
list, so the readers of it cannot expect it to always reflect the
most recent effective constraint value. However, they can and do
expect it to be equal to a valid effective constraint value computed
at a certain time in the past (event though it may not be the most
recent one), so add READ|WRITE_ONCE() annotations around the
target_value accesses to prevent the compiler from possibly causing
that expectation to be unmet by generating code in an exceptionally
convoluted way.

Signed-off-by: Qian Cai <[email protected]>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <[email protected]>

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PM: QoS: Make CPU latency QoS depend on CONFIG_CPU_IDLE

Because cpuidle is the only user of the effective constraint coming
from the CPU latency QoS, add #ifdef CONFIG_CPU_IDLE around that code
to a

PM: QoS: Make CPU latency QoS depend on CONFIG_CPU_IDLE

Because cpuidle is the only user of the effective constraint coming
from the CPU latency QoS, add #ifdef CONFIG_CPU_IDLE around that code
to avoid building it unnecessarily.

Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Reviewed-by: Amit Kucheria <[email protected]>
Tested-by: Amit Kucheria <[email protected]>

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PM: QoS: Update file information comments

Update the file information comments in include/linux/pm_qos.h
and kernel/power/qos.c by adding titles along with copyright and
authors information to them

PM: QoS: Update file information comments

Update the file information comments in include/linux/pm_qos.h
and kernel/power/qos.c by adding titles along with copyright and
authors information to them and changing the qos.c description to
better reflect its contents (outdated information is dropped from
it in particular).

Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Reviewed-by: Amit Kucheria <[email protected]>
Tested-by: Amit Kucheria <[email protected]>

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PM: QoS: Drop PM_QOS_CPU_DMA_LATENCY and rename related functions

Drop the PM QoS classes enum including PM_QOS_CPU_DMA_LATENCY,
drop the wrappers around pm_qos_request(), pm_qos_request_active(),
a

PM: QoS: Drop PM_QOS_CPU_DMA_LATENCY and rename related functions

Drop the PM QoS classes enum including PM_QOS_CPU_DMA_LATENCY,
drop the wrappers around pm_qos_request(), pm_qos_request_active(),
and pm_qos_add/update/remove_request() introduced previously, rename
these functions, respectively, to cpu_latency_qos_limit(),
cpu_latency_qos_request_active(), and
cpu_latency_qos_add/update/remove_request(), and update their
kerneldoc comments. [While at it, drop some useless comments from
these functions.]

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Reviewed-by: Amit Kucheria <[email protected]>
Tested-by: Amit Kucheria <[email protected]>

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PM: QoS: Adjust pm_qos_request() signature and reorder pm_qos.h

Change the return type of pm_qos_request() to be the same as the
one of pm_qos_read_value() called by it internally and stop exporting

PM: QoS: Adjust pm_qos_request() signature and reorder pm_qos.h

Change the return type of pm_qos_request() to be the same as the
one of pm_qos_read_value() called by it internally and stop exporting
it to modules (because its only caller, cpuidle, is not modular).

Also move the pm_qos_read_value() header away from the CPU latency
QoS API function headers in pm_qos.h (because it technically does
not belong to that API).

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Reviewed-by: Amit Kucheria <[email protected]>
Tested-by: Amit Kucheria <[email protected]>

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PM: QoS: Simplify definitions of CPU latency QoS trace events

Modify the definitions of the CPU latency QoS trace events to take
one argument (since PM_QOS_CPU_DMA_LATENCY is always passed as the
pm

PM: QoS: Simplify definitions of CPU latency QoS trace events

Modify the definitions of the CPU latency QoS trace events to take
one argument (since PM_QOS_CPU_DMA_LATENCY is always passed as the
pm_qos_class argument to them) and update the documentation of them
accordingly (while at it, make it explicitly mention CPU latency QoS
and relocate it after the device PM QoS trace events documentation).

The names and output format of the trace events do not change to
preserve user space compatibility.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Reviewed-by: Amit Kucheria <[email protected]>
Tested-by: Amit Kucheria <[email protected]>

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PM: QoS: Rename things related to the CPU latency QoS

First, rename PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE to
PM_QOS_CPU_LATENCY_DEFAULT_VALUE and update all of the code
referring to it accordingly.

Next

PM: QoS: Rename things related to the CPU latency QoS

First, rename PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE to
PM_QOS_CPU_LATENCY_DEFAULT_VALUE and update all of the code
referring to it accordingly.

Next, rename cpu_dma_constraints to cpu_latency_constraints, move
the definition of it closer to the functions referring to it and
update all of them accordingly. [While at it, add a comment to mark
the start of the code related to the CPU latency QoS.]

Finally, rename the pm_qos_power_*() family of functions and
pm_qos_power_fops to cpu_latency_qos_*() and cpu_latency_qos_fops,
respectively, and update the definition of cpu_latency_qos_miscdev.
[While at it, update the miscdev interface code start comment.]

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Acked-by: Greg Kroah-Hartman <[email protected]>
Reviewed-by: Amit Kucheria <[email protected]>
Tested-by: Amit Kucheria <[email protected]>

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PM: QoS: Drop PM_QOS_CPU_DMA_LATENCY notifier chain

Notice that pm_qos_remove_notifier() is not used at all and the only
caller of pm_qos_add_notifier() is the cpuidle core, which only needs
the PM_

PM: QoS: Drop PM_QOS_CPU_DMA_LATENCY notifier chain

Notice that pm_qos_remove_notifier() is not used at all and the only
caller of pm_qos_add_notifier() is the cpuidle core, which only needs
the PM_QOS_CPU_DMA_LATENCY notifier to invoke wake_up_all_idle_cpus()
upon changes of the PM_QOS_CPU_DMA_LATENCY target value.

First, to ensure that wake_up_all_idle_cpus() will be called
whenever the PM_QOS_CPU_DMA_LATENCY target value changes, modify the
pm_qos_add/update/remove_request() family of functions to check if
the effective constraint for the PM_QOS_CPU_DMA_LATENCY has changed
and call wake_up_all_idle_cpus() directly in that case.

Next, drop the PM_QOS_CPU_DMA_LATENCY notifier from cpuidle as it is
not necessary any more.

Finally, drop both pm_qos_add_notifier() and pm_qos_remove_notifier(),
as they have no callers now, along with cpu_dma_lat_notifier which is
only used by them.

Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Reviewed-by: Amit Kucheria <[email protected]>
Tested-by: Amit Kucheria <[email protected]>

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PM: QoS: Redefine struct pm_qos_request and drop struct pm_qos_object

First, change the definition of struct pm_qos_request so that it
contains a struct pm_qos_constraints pointer (called "qos") ins

PM: QoS: Redefine struct pm_qos_request and drop struct pm_qos_object

First, change the definition of struct pm_qos_request so that it
contains a struct pm_qos_constraints pointer (called "qos") instead
of a PM QoS class number (in preparation for dropping the PM QoS
classes concept altogether going forward) and move its definition
(along with the definition of struct pm_qos_flags_request that does
not change) after the definition of struct pm_qos_constraints.

Next, drop the definition of struct pm_qos_object and the null_pm_qos
and cpu_dma_pm_qos variables of that type along with pm_qos_array[]
holding pointers to them and change the code to refer to the
pm_qos_constraints structure directly or to use the new qos pointer
in struct pm_qos_request for that instead of going through
pm_qos_array[] to access it. Also update kerneldoc comments that
mention pm_qos_class to refer to PM_QOS_CPU_DMA_LATENCY directly
instead.

Finally, drop register_pm_qos_misc(), introduce cpu_latency_qos_miscdev
(with the name field set to "cpu_dma_latency") to implement the
CPU latency QoS interface in /dev/ and register it directly from
pm_qos_power_init().

After these changes the notion of PM QoS classes remains only in the
API (in the form of redundant function parameters that are ignored)
and in the definitions of PM QoS trace events.

While at it, some redundant local variables are dropped etc.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Reviewed-by: Amit Kucheria <[email protected]>
Tested-by: Amit Kucheria <[email protected]>

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PM: QoS: Clean up misc device file operations

Reorder the code to avoid using extra function header declarations
for the pm_qos_power_*() family of functions and drop those
declarations.

Also clean

PM: QoS: Clean up misc device file operations

Reorder the code to avoid using extra function header declarations
for the pm_qos_power_*() family of functions and drop those
declarations.

Also clean up the internals of those functions to consolidate checks,
avoid using redundant local variables and similar.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Reviewed-by: Amit Kucheria <[email protected]>
Tested-by: Amit Kucheria <[email protected]>

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PM: QoS: Drop iterations over global QoS classes

After commit c3082a674f46 ("PM: QoS: Get rid of unused flags") the
only global PM QoS class in use is PM_QOS_CPU_DMA_LATENCY, so it
does not really m

PM: QoS: Drop iterations over global QoS classes

After commit c3082a674f46 ("PM: QoS: Get rid of unused flags") the
only global PM QoS class in use is PM_QOS_CPU_DMA_LATENCY, so it
does not really make sense to iterate over global QoS classes
anywhere, since there is only one.

Remove iterations over global QoS classes from the code and use
PM_QOS_CPU_DMA_LATENCY as the target class directly where needed.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Reviewed-by: Amit Kucheria <[email protected]>
Tested-by: Amit Kucheria <[email protected]>

show more ...

PM: QoS: Clean up pm_qos_read_value() and pm_qos_get/set_value()

Move the definition of pm_qos_read_value() before the one of
pm_qos_get_value() and add a kerneldoc comment to it (as it is
not stati

PM: QoS: Clean up pm_qos_read_value() and pm_qos_get/set_value()

Move the definition of pm_qos_read_value() before the one of
pm_qos_get_value() and add a kerneldoc comment to it (as it is
not static).

Also replace the BUG() in pm_qos_get_value() with WARN() (to
prevent the kernel from crashing if an unknown PM QoS type is
used by mistake) and drop the comment next to it that is not
necessary any more.

Additionally, drop the unnecessary inline modifier from the header
of pm_qos_set_value().

Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Reviewed-by: Amit Kucheria <[email protected]>
Tested-by: Amit Kucheria <[email protected]>

show more ...

PM: QoS: Clean up pm_qos_update_target() and pm_qos_update_flags()

Clean up the pm_qos_update_target() function:
* Update its kerneldoc comment.
* Drop the redundant ret local variable from it.
*

PM: QoS: Clean up pm_qos_update_target() and pm_qos_update_flags()

Clean up the pm_qos_update_target() function:
* Update its kerneldoc comment.
* Drop the redundant ret local variable from it.
* Reorder definitions of local variables in it.
* Update a comment in it.

Also update the kerneldoc comment of pm_qos_update_flags() (e.g.
notifiers are not called by it any more) and add one emtpy line
to its body (for more visual clarity).

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Reviewed-by: Amit Kucheria <[email protected]>
Tested-by: Amit Kucheria <[email protected]>

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PM: QoS: Drop the PM_QOS_SUM QoS type

The PM_QOS_SUM QoS type is not used, so drop it along with the
code referring to it in pm_qos_get_value() and the related local
variables in there.

No intentio

PM: QoS: Drop the PM_QOS_SUM QoS type

The PM_QOS_SUM QoS type is not used, so drop it along with the
code referring to it in pm_qos_get_value() and the related local
variables in there.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Reviewed-by: Amit Kucheria <[email protected]>
Tested-by: Amit Kucheria <[email protected]>

show more ...

PM: QoS: Drop pm_qos_update_request_timeout()

The pm_qos_update_request_timeout() function is not called from
anywhere, so drop it along with the work member in struct
pm_qos_request needed by it.

PM: QoS: Drop pm_qos_update_request_timeout()

The pm_qos_update_request_timeout() function is not called from
anywhere, so drop it along with the work member in struct
pm_qos_request needed by it.

Also drop the useless pm_qos_update_request_timeout trace event
that is only triggered by that function (so it never triggers at
all) and update the trace events documentation accordingly.

Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Reviewed-by: Amit Kucheria <[email protected]>
Tested-by: Amit Kucheria <[email protected]>

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PM: QoS: Drop debugfs interface

After commit c3082a674f46 ("PM: QoS: Get rid of unused flags") the
only global PM QoS class in use is PM_QOS_CPU_DMA_LATENCY and the
existing PM QoS debugfs interface

PM: QoS: Drop debugfs interface

After commit c3082a674f46 ("PM: QoS: Get rid of unused flags") the
only global PM QoS class in use is PM_QOS_CPU_DMA_LATENCY and the
existing PM QoS debugfs interface has become overly complicated (as
it takes other potentially possible PM QoS classes that are not there
any more into account). It is also not particularly useful (the
"type" of the PM_QOS_CPU_DMA_LATENCY is known, its aggregate value
can be read from /dev/cpu_dma_latency and the number of requests in
the queue does not really matter) and there are no known users
depending on it. Moreover, there are dedicated trace events that
can be used for tracking PM QoS usage with much higher precision.

For these reasons, drop the PM QoS debugfs interface altogether.

Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>

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PM / QoS: Restore DEV_PM_QOS_MIN/MAX_FREQUENCY

Support for adding per-device frequency limits was removed in
commit 2aac8bdf7a0f ("PM: QoS: Drop frequency QoS types from device PM QoS")
after cpufre

PM / QoS: Restore DEV_PM_QOS_MIN/MAX_FREQUENCY

Support for adding per-device frequency limits was removed in
commit 2aac8bdf7a0f ("PM: QoS: Drop frequency QoS types from device PM QoS")
after cpufreq switched to use a new "freq_constraints" construct.

Restore support for per-device freq limits but base this upon
freq_constraints. This is primarily meant to be used by the devfreq
subsystem.

This removes the "static" marking on freq_qos_apply but does not export
it for modules.

Signed-off-by: Leonard Crestez <[email protected]>
Reviewed-by: Matthias Kaehlcke <[email protected]>
Tested-by: Matthias Kaehlcke <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

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PM: QoS: Invalidate frequency QoS requests after removal

Switching cpufreq drivers (or switching operation modes of the
intel_pstate driver from "active" to "passive" and vice versa)
does not work o

PM: QoS: Invalidate frequency QoS requests after removal

Switching cpufreq drivers (or switching operation modes of the
intel_pstate driver from "active" to "passive" and vice versa)
does not work on some x86 systems with ACPI after commit
3000ce3c52f8 ("cpufreq: Use per-policy frequency QoS"), because
the ACPI _PPC and thermal code uses the same frequency QoS request
object for a given CPU every time a cpufreq driver is registered
and freq_qos_remove_request() does not invalidate the request after
removing it from its QoS list, so freq_qos_add_request() complains
and fails when that request is passed to it again.

Fix the issue by modifying freq_qos_remove_request() to clear the qos
and type fields of the frequency request pointed to by its argument
after removing it from its QoS list so as to invalidate it.

Fixes: 3000ce3c52f8 ("cpufreq: Use per-policy frequency QoS")
Reported-and-tested-by: Doug Smythies <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
Acked-by: Viresh Kumar <[email protected]>

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PM: QoS: Introduce frequency QoS

Introduce frequency QoS, based on the "raw" low-level PM QoS, to
represent min and max frequency requests and aggregate constraints.

The min and max frequency reque

PM: QoS: Introduce frequency QoS

Introduce frequency QoS, based on the "raw" low-level PM QoS, to
represent min and max frequency requests and aggregate constraints.

The min and max frequency requests are to be represented by
struct freq_qos_request objects and the aggregate constraints are to
be represented by struct freq_constraints objects. The latter are
expected to be initialized with the help of freq_constraints_init().

The freq_qos_read_value() helper is defined to retrieve the aggregate
constraints values from a given struct freq_constraints object and
there are the freq_qos_add_request(), freq_qos_update_request() and
freq_qos_remove_request() helpers to manipulate the min and max
frequency requests. It is assumed that the the helpers will not
run concurrently with each other for the same struct freq_qos_request
object, so if that may be the case, their uses must ensure proper
synchronization between them (e.g. through locking).

In addition, freq_qos_add_notifier() and freq_qos_remove_notifier()
are provided to add and remove notifiers that will trigger on aggregate
constraint changes to and from a given struct freq_constraints object,
respectively.

Signed-off-by: Rafael J. Wysocki <[email protected]>
Acked-by: Viresh Kumar <[email protected]>

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PM: QoS: Get rid of unused flags

The network_latency and network_throughput flags for PM-QoS have not
found much use in drivers or in userspace since they were introduced.

Commit 4a733ef1bea7 ("mac

PM: QoS: Get rid of unused flags

The network_latency and network_throughput flags for PM-QoS have not
found much use in drivers or in userspace since they were introduced.

Commit 4a733ef1bea7 ("mac80211: remove PM-QoS listener") removed the
only user PM_QOS_NETWORK_LATENCY in the kernel a while ago and there
don't seem to be any userspace tools using the character device files
either.

PM_QOS_MEMORY_BANDWIDTH was never even added to the trace events.

Remove all the flags except cpu_dma_latency.

Signed-off-by: Amit Kucheria <[email protected]>
Acked-by: Pavel Machek <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

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treewide: Add SPDX license identifier for missed files

Add SPDX license identifiers to all files which:

- Have no license information of any form

- Have EXPORT_.*_SYMBOL_GPL inside which was use

treewide: Add SPDX license identifier for missed files

Add SPDX license identifiers to all files which:

- Have no license information of any form

- Have EXPORT_.*_SYMBOL_GPL inside which was used in the
initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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