linux-stable.git/drivers/acpi/processor_perflib.c, branch linux-5.4.y

ACPI: processor: perflib: Move problematic pr->performance check

2025-08-28T14:21:24+00:00

commit d405ec23df13e6df599f5bd965a55d13420366b8 upstream.

Commit d33bd88ac0eb ("ACPI: processor: perflib: Fix initial _PPC limit
application") added a pr->performance check that prevents the frequency
QoS request from being added when the given processor has no performance
object.  Unfortunately, this causes a WARN() in freq_qos_remove_request()
to trigger on an attempt to take the given CPU offline later because the
frequency QoS object has not been added for it due to the missing
performance object.

Address this by moving the pr->performance check before calling
acpi_processor_get_platform_limit() so it only prevents a limit from
being set for the CPU if the performance object is not present.  This
way, the frequency QoS request is added as it was before the above
commit and it is present all the time along with the CPU's cpufreq
policy regardless of whether or not the CPU is online.

Fixes: d33bd88ac0eb ("ACPI: processor: perflib: Fix initial _PPC limit application")
Tested-by: Rafael J. Wysocki 
Cc: 5.4+  # 5.4+
Signed-off-by: Rafael J. Wysocki 
Link: https://patch.msgid.link/2801421.mvXUDI8C0e@rafael.j.wysocki
Signed-off-by: Greg Kroah-Hartman

ACPI: processor: perflib: Fix initial _PPC limit application

2025-08-28T14:21:23+00:00

commit d33bd88ac0ebb49e7f7c8f29a8c7ee9eae85d765 upstream.

If the BIOS sets a _PPC frequency limit upfront, it will fail to take
effect due to a call ordering issue.  Namely, freq_qos_update_request()
is called before freq_qos_add_request() for the given request causing
the constraint update to be ignored.  The call sequence in question is
as follows:

cpufreq_policy_online()
  acpi_cpufreq_cpu_init()
    acpi_processor_register_performance()
      acpi_processor_get_performance_info()
        acpi_processor_get_platform_limit()
         freq_qos_update_request(&perflib_req) <- inactive QoS request
  blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
                               CPUFREQ_CREATE_POLICY)
    acpi_processor_notifier()
      acpi_processor_ppc_init()
        freq_qos_add_request(&perflib_req) <- QoS request activation

Address this by adding an acpi_processor_get_platform_limit() call
to acpi_processor_ppc_init(), after the perflib_req activation via
freq_qos_add_request(), which causes the initial _PPC limit to be
picked up as appropriate.  However, also ensure that the _PPC limit
will not be picked up in the cases when the cpufreq driver does not
call acpi_processor_register_performance() by adding a pr->performance
check to the related_cpus loop in acpi_processor_ppc_init().

Fixes: d15ce412737a ("ACPI: cpufreq: Switch to QoS requests instead of cpufreq notifier")
Signed-off-by: Jiayi Li 
Link: https://patch.msgid.link/20250721032606.3459369-1-lijiayi@kylinos.cn
[ rjw: Consolidate pr-related checks in acpi_processor_ppc_init() ]
[ rjw: Subject and changelog adjustments ]
Cc: 5.4+  # 5.4+: 2d8b39a62a5d ACPI: processor: Avoid NULL pointer dereferences at init time
Cc: 5.4+  # 5.4+: 3000ce3c52f8 cpufreq: Use per-policy frequency QoS
Cc: 5.4+  # 5.4+: a1bb46c36ce3 ACPI: processor: Add QoS requests for all CPUs
Cc: 5.4+  # 5.4+
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

ACPI: processor: perflib: Avoid updating frequency QoS unnecessarily

2023-08-11T09:53:53+00:00

commit 99387b016022c29234c4ebf9abd34358c6e56532 upstream.

Modify acpi_processor_get_platform_limit() to avoid updating its
frequency QoS request when the _PPC return value has not changed
by comparing that value to the previous _PPC return value stored in
the performance_platform_limit field of the struct acpi_processor
corresponding to the given CPU.

While at it, do the _PPC return value check against the state count
earlier, to avoid setting performance_platform_limit to an invalid
value, and make acpi_processor_ppc_init() use FREQ_QOS_MAX_DEFAULT_VALUE
as the "no limit" frequency QoS for consistency.

Signed-off-by: Rafael J. Wysocki 
Tested-by: Hagar Hemdan 
Signed-off-by: Greg Kroah-Hartman

ACPI: processor: perflib: Use the "no limit" frequency QoS

2023-08-11T09:53:53+00:00

commit c02d5feb6e2f60affc6ba8606d8d614c071e2ba6 upstream.

When _PPC returns 0, it means that the CPU frequency is not limited by
the platform firmware, so make acpi_processor_get_platform_limit()
update the frequency QoS request used by it to "no limit" in that case.

This addresses a problem with limiting CPU frequency artificially on
some systems after CPU offline/online to the frequency that corresponds
to the first entry in the _PSS return package.

Reported-by: Pratyush Yadav 
Signed-off-by: Rafael J. Wysocki 
Reviewed-by: Pratyush Yadav 
Tested-by: Pratyush Yadav 
Tested-by: Hagar Hemdan 
Signed-off-by: Greg Kroah-Hartman

ACPI: processor: Add QoS requests for all CPUs

2019-10-25T09:33:48+00:00

The _PPC change notifications from the platform firmware are per-CPU,
so acpi_processor_ppc_init() needs to add a frequency QoS request
for each CPU covered by a cpufreq policy to take all of them into
account.

Even though ACPI thermal control of CPUs sets frequency limits
per processor package, it also needs a frequency QoS request for each
CPU in a cpufreq policy in case some of them are taken offline and
the frequency limit needs to be set through the remaining online
ones (this is slightly excessive, because all CPUs covered by one
cpufreq policy will set the same frequency limit through their QoS
requests, but it is not incorrect).

Modify the code in accordance with the above observations.

Fixes: d15ce412737a ("ACPI: cpufreq: Switch to QoS requests instead of cpufreq notifier")
Signed-off-by: Rafael J. Wysocki 
Acked-by: Viresh Kumar

cpufreq: Use per-policy frequency QoS

2019-10-21T00:05:21+00:00

Replace the CPU device PM QoS used for the management of min and max
frequency constraints in cpufreq (and its users) with per-policy
frequency QoS to avoid problems with cpufreq policies covering
more then one CPU.

Namely, a cpufreq driver is registered with the subsys interface
which calls cpufreq_add_dev() for each CPU, starting from CPU0, so
currently the PM QoS notifiers are added to the first CPU in the
policy (i.e. CPU0 in the majority of cases).

In turn, when the cpufreq driver is unregistered, the subsys interface
doing that calls cpufreq_remove_dev() for each CPU, starting from CPU0,
and the PM QoS notifiers are only removed when cpufreq_remove_dev() is
called for the last CPU in the policy, say CPUx, which as a rule is
not CPU0 if the policy covers more than one CPU.  Then, the PM QoS
notifiers cannot be removed, because CPUx does not have them, and
they are still there in the device PM QoS notifiers list of CPU0,
which prevents new PM QoS notifiers from being registered for CPU0
on the next attempt to register the cpufreq driver.

The same issue occurs when the first CPU in the policy goes offline
before unregistering the driver.

After this change it does not matter which CPU is the policy CPU at
the driver registration time and whether or not it is online all the
time, because the frequency QoS is per policy and not per CPU.

Fixes: 67d874c3b2c6 ("cpufreq: Register notifiers with the PM QoS framework")
Reported-by: Dmitry Osipenko 
Tested-by: Dmitry Osipenko 
Reported-by: Sudeep Holla 
Tested-by: Sudeep Holla 
Diagnosed-by: Viresh Kumar 
Link: https://lore.kernel.org/linux-pm/5ad2624194baa2f53acc1f1e627eb7684c577a19.1562210705.git.viresh.kumar@linaro.org/T/#md2d89e95906b8c91c15f582146173dce2e86e99f
Link: https://lore.kernel.org/linux-pm/20191017094612.6tbkwoq4harsjcqv@vireshk-i7/T/#m30d48cc23b9a80467fbaa16e30f90b3828a5a29b
Signed-off-by: Rafael J. Wysocki 
Acked-by: Viresh Kumar

ACPI: processor: Avoid NULL pointer dereferences at init time

2019-10-16T11:02:45+00:00

If there are neither processor objects nor processor device objects
in the ACPI tables, the per-CPU processors table will not be
initialized and attempting to dereference pointers from there will
cause the kernel to crash.  This happens in acpi_processor_ppc_init()
and acpi_thermal_cpufreq_init() after commit d15ce412737a ("ACPI:
cpufreq: Switch to QoS requests instead of cpufreq notifier")
which didn't add the requisite NULL pointer checks in there.

Add the NULL pointer checks to acpi_processor_ppc_init() and
acpi_thermal_cpufreq_init(), and to the corresponding "exit"
routines.

While at it, drop redundant return instructions from
acpi_processor_ppc_init() and acpi_thermal_cpufreq_init().

Fixes: d15ce412737a ("ACPI: cpufreq: Switch to QoS requests instead of cpufreq notifier")
Reported-by: Srinivas Pandruvada 
Signed-off-by: Rafael J. Wysocki 
Acked-by: Viresh Kumar

ACPI: cpufreq: Switch to QoS requests instead of cpufreq notifier

2019-08-28T09:21:53+00:00

The cpufreq core now takes the min/max frequency constraints via QoS
requests and the CPUFREQ_ADJUST notifier shall get removed later on.

Switch over to using the QoS request for maximum frequency constraint
for acpi driver.

Signed-off-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157

2019-05-30T18:26:37+00:00

Based on 3 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [kishon] [vijay] [abraham]
  [i] [kishon]@[ti] [com] this program is distributed in the hope that
  it will be useful but without any warranty without even the implied
  warranty of merchantability or fitness for a particular purpose see
  the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [graeme] [gregory]
  [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
  [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
  [hk] [hemahk]@[ti] [com] this program is distributed in the hope
  that it will be useful but without any warranty without even the
  implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Reviewed-by: Richard Fontana 
Reviewed-by: Kate Stewart 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman

cpufreq: intel_pstate: Driver-specific handling of _PPC updates

2019-04-01T21:43:05+00:00

In some cases, the platform firmware disables or enables turbo
frequencies for all CPUs globally before triggering a _PPC change
notification for one of them.  Obviously, that global change affects
all CPUs, not just the notified one, and it needs to be acted upon by
cpufreq.

The intel_pstate driver is able to detect such global changes of
the settings, but it also needs to update policy limits for all
CPUs if that happens, in particular if turbo frequencies are
enabled globally - to allow them to be used.

For this reason, introduce a new cpufreq driver callback to be
invoked on _PPC notifications, if present, instead of simply
calling cpufreq_update_policy() for the notified CPU and make
intel_pstate use it to trigger policy updates for all CPUs
in the system if global settings change.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=200759
Reported-by: Gabriele Mazzotta 
Tested-by: Gabriele Mazzotta 
Signed-off-by: Rafael J. Wysocki 
Acked-by: Viresh Kumar