<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/cpufreq, branch linux-6.16.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>cpufreq: Initialize cpufreq-based invariance before subsys</title>
<updated>2025-10-02T11:48:27+00:00</updated>
<author>
<name>Christian Loehle</name>
<email>christian.loehle@arm.com</email>
</author>
<published>2025-09-18T10:15:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=302c25ec64051774b2f59e2abc83c7f498dbb7ce'/>
<id>302c25ec64051774b2f59e2abc83c7f498dbb7ce</id>
<content type='text'>
[ Upstream commit 8ffe28b4e8d8b18cb2f2933410322c24f039d5d6 ]

commit 2a6c72738706 ("cpufreq: Initialize cpufreq-based
frequency-invariance later") postponed the frequency invariance
initialization to avoid disabling it in the error case.
This isn't locking safe, instead move the initialization up before
the subsys interface is registered (which will rebuild the
sched_domains) and add the corresponding disable on the error path.

Observed lockdep without this patch:
[    0.989686] ======================================================
[    0.989688] WARNING: possible circular locking dependency detected
[    0.989690] 6.17.0-rc4-cix-build+ #31 Tainted: G S
[    0.989691] ------------------------------------------------------
[    0.989692] swapper/0/1 is trying to acquire lock:
[    0.989693] ffff800082ada7f8 (sched_energy_mutex){+.+.}-{4:4}, at: rebuild_sched_domains_energy+0x30/0x58
[    0.989705]
               but task is already holding lock:
[    0.989706] ffff000088c89bc8 (&amp;policy-&gt;rwsem){+.+.}-{4:4}, at: cpufreq_online+0x7f8/0xbe0
[    0.989713]
               which lock already depends on the new lock.

Fixes: 2a6c72738706 ("cpufreq: Initialize cpufreq-based frequency-invariance later")
Signed-off-by: Christian Loehle &lt;christian.loehle@arm.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 8ffe28b4e8d8b18cb2f2933410322c24f039d5d6 ]

commit 2a6c72738706 ("cpufreq: Initialize cpufreq-based
frequency-invariance later") postponed the frequency invariance
initialization to avoid disabling it in the error case.
This isn't locking safe, instead move the initialization up before
the subsys interface is registered (which will rebuild the
sched_domains) and add the corresponding disable on the error path.

Observed lockdep without this patch:
[    0.989686] ======================================================
[    0.989688] WARNING: possible circular locking dependency detected
[    0.989690] 6.17.0-rc4-cix-build+ #31 Tainted: G S
[    0.989691] ------------------------------------------------------
[    0.989692] swapper/0/1 is trying to acquire lock:
[    0.989693] ffff800082ada7f8 (sched_energy_mutex){+.+.}-{4:4}, at: rebuild_sched_domains_energy+0x30/0x58
[    0.989705]
               but task is already holding lock:
[    0.989706] ffff000088c89bc8 (&amp;policy-&gt;rwsem){+.+.}-{4:4}, at: cpufreq_online+0x7f8/0xbe0
[    0.989713]
               which lock already depends on the new lock.

Fixes: 2a6c72738706 ("cpufreq: Initialize cpufreq-based frequency-invariance later")
Signed-off-by: Christian Loehle &lt;christian.loehle@arm.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PM: EM: Add function for registering a PD without capacity update</title>
<updated>2025-09-19T14:37:30+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2025-09-05T13:44:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1f6a55e9ce453e36aaf293d0ec5929adf87e6b74'/>
<id>1f6a55e9ce453e36aaf293d0ec5929adf87e6b74</id>
<content type='text'>
commit e0423541477dfb684fbc6e6b5386054bc650f264 upstream.

The intel_pstate driver manages CPU capacity changes itself and it does
not need an update of the capacity of all CPUs in the system to be
carried out after registering a PD.

Moreover, in some configurations (for instance, an SMT-capable
hybrid x86 system booted with nosmt in the kernel command line) the
em_check_capacity_update() call at the end of em_dev_register_perf_domain()
always fails and reschedules itself to run once again in 1 s, so
effectively it runs in vain every 1 s forever.

To address this, introduce a new variant of em_dev_register_perf_domain(),
called em_dev_register_pd_no_update(), that does not invoke
em_check_capacity_update(), and make intel_pstate use it instead of the
original.

Fixes: 7b010f9b9061 ("cpufreq: intel_pstate: EAS support for hybrid platforms")
Closes: https://lore.kernel.org/linux-pm/40212796-734c-4140-8a85-854f72b8144d@panix.com/
Reported-by: Kenneth R. Crudup &lt;kenny@panix.com&gt;
Tested-by: Kenneth R. Crudup &lt;kenny@panix.com&gt;
Cc: 6.16+ &lt;stable@vger.kernel.org&gt; # 6.16+
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit e0423541477dfb684fbc6e6b5386054bc650f264 upstream.

The intel_pstate driver manages CPU capacity changes itself and it does
not need an update of the capacity of all CPUs in the system to be
carried out after registering a PD.

Moreover, in some configurations (for instance, an SMT-capable
hybrid x86 system booted with nosmt in the kernel command line) the
em_check_capacity_update() call at the end of em_dev_register_perf_domain()
always fails and reschedules itself to run once again in 1 s, so
effectively it runs in vain every 1 s forever.

To address this, introduce a new variant of em_dev_register_perf_domain(),
called em_dev_register_pd_no_update(), that does not invoke
em_check_capacity_update(), and make intel_pstate use it instead of the
original.

Fixes: 7b010f9b9061 ("cpufreq: intel_pstate: EAS support for hybrid platforms")
Closes: https://lore.kernel.org/linux-pm/40212796-734c-4140-8a85-854f72b8144d@panix.com/
Reported-by: Kenneth R. Crudup &lt;kenny@panix.com&gt;
Tested-by: Kenneth R. Crudup &lt;kenny@panix.com&gt;
Cc: 6.16+ &lt;stable@vger.kernel.org&gt; # 6.16+
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq/amd-pstate: Fix a regression leading to EPP 0 after resume</title>
<updated>2025-09-19T14:37:29+00:00</updated>
<author>
<name>Mario Limonciello (AMD)</name>
<email>superm1@kernel.org</email>
</author>
<published>2025-08-26T05:27:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9c48608e3243cf10310c652500c1903cfeb40bfc'/>
<id>9c48608e3243cf10310c652500c1903cfeb40bfc</id>
<content type='text'>
[ Upstream commit ba3319e5905710abe495b11a1aaf03ebb51d62e2 ]

During the suspend sequence the cached CPPC request is destroyed
with the expectation that it's restored during resume.  This assumption
broke when the separate cache EPP variable was removed, and then it was
broken again by commit 608a76b65288 ("cpufreq/amd-pstate: Add support
for the "Requested CPU Min frequency" BIOS option") which explicitly
set it to zero during suspend.

Remove the invalidation and set the value during the suspend call to
update limits so that the cached variable can be used to restore on
resume.

Fixes: 608a76b65288 ("cpufreq/amd-pstate: Add support for the "Requested CPU Min frequency" BIOS option")
Fixes: b7a41156588a ("cpufreq/amd-pstate: Invalidate cppc_req_cached during suspend")
Reported-by: goldens &lt;goldenspinach.rhbugzilla@gmail.com&gt;
Closes: https://community.frame.work/t/increased-power-usage-after-resuming-from-suspend-on-ryzen-7040-kernel-6-15-regression/
Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2391221
Tested-by: goldens &lt;goldenspinach.rhbugzilla@gmail.com&gt;
Tested-by: Willian Wang &lt;kernel@willian.wang&gt;
Reported-by: Vincent Mauirn &lt;vincent.maurin.fr@gmail.com&gt;
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219981
Tested-by: Alex De Lorenzo &lt;kernel@alexdelorenzo.dev&gt;
Reviewed-by: Gautham R. Shenoy &lt;gautham.shenoy@amd.com&gt;
Link: https://lore.kernel.org/r/20250826052747.2240670-1-superm1@kernel.org
Signed-off-by: Mario Limonciello (AMD) &lt;superm1@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit ba3319e5905710abe495b11a1aaf03ebb51d62e2 ]

During the suspend sequence the cached CPPC request is destroyed
with the expectation that it's restored during resume.  This assumption
broke when the separate cache EPP variable was removed, and then it was
broken again by commit 608a76b65288 ("cpufreq/amd-pstate: Add support
for the "Requested CPU Min frequency" BIOS option") which explicitly
set it to zero during suspend.

Remove the invalidation and set the value during the suspend call to
update limits so that the cached variable can be used to restore on
resume.

Fixes: 608a76b65288 ("cpufreq/amd-pstate: Add support for the "Requested CPU Min frequency" BIOS option")
Fixes: b7a41156588a ("cpufreq/amd-pstate: Invalidate cppc_req_cached during suspend")
Reported-by: goldens &lt;goldenspinach.rhbugzilla@gmail.com&gt;
Closes: https://community.frame.work/t/increased-power-usage-after-resuming-from-suspend-on-ryzen-7040-kernel-6-15-regression/
Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2391221
Tested-by: goldens &lt;goldenspinach.rhbugzilla@gmail.com&gt;
Tested-by: Willian Wang &lt;kernel@willian.wang&gt;
Reported-by: Vincent Mauirn &lt;vincent.maurin.fr@gmail.com&gt;
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219981
Tested-by: Alex De Lorenzo &lt;kernel@alexdelorenzo.dev&gt;
Reviewed-by: Gautham R. Shenoy &lt;gautham.shenoy@amd.com&gt;
Link: https://lore.kernel.org/r/20250826052747.2240670-1-superm1@kernel.org
Signed-off-by: Mario Limonciello (AMD) &lt;superm1@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq/amd-pstate: Fix setting of CPPC.min_perf in active mode for performance governor</title>
<updated>2025-09-19T14:37:28+00:00</updated>
<author>
<name>Gautham R. Shenoy</name>
<email>gautham.shenoy@amd.com</email>
</author>
<published>2025-08-21T04:26:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a330f6a521eebb303c79dae323716222bf8af632'/>
<id>a330f6a521eebb303c79dae323716222bf8af632</id>
<content type='text'>
[ Upstream commit 220abf77e7c2835cc63ea8cd7158cf83952640af ]

In the "active" mode of the amd-pstate driver with performance
governor, the CPPC.min_perf is expected to be the nominal_perf.

However after commit a9b9b4c2a4cd ("cpufreq/amd-pstate: Drop min and
max cached frequencies"), this is not the case when the governor is
switched from performance to powersave and back to performance, and
the CPPC.min_perf will be equal to the scaling_min_freq that was set
for the powersave governor.

This is because prior to commit a9b9b4c2a4cd ("cpufreq/amd-pstate:
Drop min and max cached frequencies"), amd_pstate_epp_update_limit()
would unconditionally call amd_pstate_update_min_max_limit() and the
latter function would enforce the CPPC.min_perf constraint when the
governor is performance.

However, after the aforementioned commit,
amd_pstate_update_min_max_limit() is called by
amd_pstate_epp_update_limit() only when either the
scaling_{min/max}_freq is different from the cached value of
cpudata-&gt;{min/max}_limit_freq, which wouldn't have changed on a
governor transition from powersave to performance, thus missing out on
enforcing the CPPC.min_perf constraint for the performance governor.

Fix this by invoking amd_pstate_epp_udpate_limit() not only when the
{min/max} limits have changed from the cached values, but also when
the policy itself has changed.

Fixes: a9b9b4c2a4cd ("cpufreq/amd-pstate: Drop min and max cached frequencies")
Signed-off-by: Gautham R. Shenoy &lt;gautham.shenoy@amd.com&gt;
Reviewed-by: Mario Limonciello &lt;mario.limonciello@amd.com&gt;
Link: https://lore.kernel.org/r/20250821042638.356-1-gautham.shenoy@amd.com
Signed-off-by: Mario Limonciello (AMD) &lt;superm1@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 220abf77e7c2835cc63ea8cd7158cf83952640af ]

In the "active" mode of the amd-pstate driver with performance
governor, the CPPC.min_perf is expected to be the nominal_perf.

However after commit a9b9b4c2a4cd ("cpufreq/amd-pstate: Drop min and
max cached frequencies"), this is not the case when the governor is
switched from performance to powersave and back to performance, and
the CPPC.min_perf will be equal to the scaling_min_freq that was set
for the powersave governor.

This is because prior to commit a9b9b4c2a4cd ("cpufreq/amd-pstate:
Drop min and max cached frequencies"), amd_pstate_epp_update_limit()
would unconditionally call amd_pstate_update_min_max_limit() and the
latter function would enforce the CPPC.min_perf constraint when the
governor is performance.

However, after the aforementioned commit,
amd_pstate_update_min_max_limit() is called by
amd_pstate_epp_update_limit() only when either the
scaling_{min/max}_freq is different from the cached value of
cpudata-&gt;{min/max}_limit_freq, which wouldn't have changed on a
governor transition from powersave to performance, thus missing out on
enforcing the CPPC.min_perf constraint for the performance governor.

Fix this by invoking amd_pstate_epp_udpate_limit() not only when the
{min/max} limits have changed from the cached values, but also when
the policy itself has changed.

Fixes: a9b9b4c2a4cd ("cpufreq/amd-pstate: Drop min and max cached frequencies")
Signed-off-by: Gautham R. Shenoy &lt;gautham.shenoy@amd.com&gt;
Reviewed-by: Mario Limonciello &lt;mario.limonciello@amd.com&gt;
Link: https://lore.kernel.org/r/20250821042638.356-1-gautham.shenoy@amd.com
Signed-off-by: Mario Limonciello (AMD) &lt;superm1@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: armada-8k: Fix off by one in armada_8k_cpufreq_free_table()</title>
<updated>2025-08-28T14:34:12+00:00</updated>
<author>
<name>Dan Carpenter</name>
<email>dan.carpenter@linaro.org</email>
</author>
<published>2025-07-01T22:30:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a7a22cc80550004c67d72dae2bd9352a773cacb9'/>
<id>a7a22cc80550004c67d72dae2bd9352a773cacb9</id>
<content type='text'>
commit 4a26df233266a628157d7f0285451d8655defdfc upstream.

The freq_tables[] array has num_possible_cpus() elements so, to avoid an
out of bounds access, this loop should be capped at "&lt; nb_cpus" instead
of "&lt;= nb_cpus".  The freq_tables[] array is allocated in
armada_8k_cpufreq_init().

Cc: stable@vger.kernel.org
Fixes: f525a670533d ("cpufreq: ap806: add cpufreq driver for Armada 8K")
Signed-off-by: Dan Carpenter &lt;dan.carpenter@linaro.org&gt;
Signed-off-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 4a26df233266a628157d7f0285451d8655defdfc upstream.

The freq_tables[] array has num_possible_cpus() elements so, to avoid an
out of bounds access, this loop should be capped at "&lt; nb_cpus" instead
of "&lt;= nb_cpus".  The freq_tables[] array is allocated in
armada_8k_cpufreq_init().

Cc: stable@vger.kernel.org
Fixes: f525a670533d ("cpufreq: ap806: add cpufreq driver for Armada 8K")
Signed-off-by: Dan Carpenter &lt;dan.carpenter@linaro.org&gt;
Signed-off-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: intel_pstate: Add Granite Rapids support in no-HWP mode</title>
<updated>2025-08-20T16:40:58+00:00</updated>
<author>
<name>Li RongQing</name>
<email>lirongqing@baidu.com</email>
</author>
<published>2025-06-23T10:56:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f45d022fcfe8c0bd46b8f9e92e3d830607c45848'/>
<id>f45d022fcfe8c0bd46b8f9e92e3d830607c45848</id>
<content type='text'>
[ Upstream commit fc64e0421598aaa87d61184f6777b52614a095be ]

Users may disable HWP in firmware, in which case intel_pstate
wouldn't load unless the CPU model is explicitly supported.

Signed-off-by: Li RongQing &lt;lirongqing@baidu.com&gt;
Link: https://patch.msgid.link/20250623105601.3924-1-lirongqing@baidu.com
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit fc64e0421598aaa87d61184f6777b52614a095be ]

Users may disable HWP in firmware, in which case intel_pstate
wouldn't load unless the CPU model is explicitly supported.

Signed-off-by: Li RongQing &lt;lirongqing@baidu.com&gt;
Link: https://patch.msgid.link/20250623105601.3924-1-lirongqing@baidu.com
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: Exit governor when failed to start old governor</title>
<updated>2025-08-20T16:40:58+00:00</updated>
<author>
<name>Lifeng Zheng</name>
<email>zhenglifeng1@huawei.com</email>
</author>
<published>2025-07-09T10:41:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=66336000b49eae54c104b8b5eb31f76a8efe51d3'/>
<id>66336000b49eae54c104b8b5eb31f76a8efe51d3</id>
<content type='text'>
[ Upstream commit 0ae204405095abfbc2d694ee0fbb49bcbbe55c57 ]

Detect the result of starting old governor in cpufreq_set_policy(). If it
fails, exit the governor and clear policy-&gt;governor.

Signed-off-by: Lifeng Zheng &lt;zhenglifeng1@huawei.com&gt;
Link: https://patch.msgid.link/20250709104145.2348017-5-zhenglifeng1@huawei.com
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 0ae204405095abfbc2d694ee0fbb49bcbbe55c57 ]

Detect the result of starting old governor in cpufreq_set_policy(). If it
fails, exit the governor and clear policy-&gt;governor.

Signed-off-by: Lifeng Zheng &lt;zhenglifeng1@huawei.com&gt;
Link: https://patch.msgid.link/20250709104145.2348017-5-zhenglifeng1@huawei.com
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: CPPC: Mark driver with NEED_UPDATE_LIMITS flag</title>
<updated>2025-08-20T16:40:56+00:00</updated>
<author>
<name>Prashant Malani</name>
<email>pmalani@google.com</email>
</author>
<published>2025-07-22T05:55:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e38b04484cb9988b85cbdf04a9bb3a8ce911371c'/>
<id>e38b04484cb9988b85cbdf04a9bb3a8ce911371c</id>
<content type='text'>
[ Upstream commit 0a1416a49e63c320f6e6c1c8d07e1b58c0d4a3f3 ]

AMU counters on certain CPPC-based platforms tend to yield inaccurate
delivered performance measurements on systems that are idle/mostly idle.
This results in an inaccurate frequency being stored by cpufreq in its
policy structure when the CPU is brought online. [1]

Consequently, if the userspace governor tries to set the frequency to a
new value, there is a possibility that it would be the erroneous value
stored earlier. In such a scenario, cpufreq would assume that the
requested frequency has already been set and return early, resulting in
the correct/new frequency request never making it to the hardware.

Since the operating frequency is liable to this sort of inconsistency,
mark the CPPC driver with CPUFREQ_NEED_UPDATE_LIMITS so that it is always
invoked when a target frequency update is requested.

Link: https://lore.kernel.org/linux-pm/20250619000925.415528-3-pmalani@google.com/ [1]
Suggested-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Prashant Malani &lt;pmalani@google.com&gt;
Acked-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
Link: https://patch.msgid.link/20250722055611.130574-2-pmalani@google.com
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 0a1416a49e63c320f6e6c1c8d07e1b58c0d4a3f3 ]

AMU counters on certain CPPC-based platforms tend to yield inaccurate
delivered performance measurements on systems that are idle/mostly idle.
This results in an inaccurate frequency being stored by cpufreq in its
policy structure when the CPU is brought online. [1]

Consequently, if the userspace governor tries to set the frequency to a
new value, there is a possibility that it would be the erroneous value
stored earlier. In such a scenario, cpufreq would assume that the
requested frequency has already been set and return early, resulting in
the correct/new frequency request never making it to the hardware.

Since the operating frequency is liable to this sort of inconsistency,
mark the CPPC driver with CPUFREQ_NEED_UPDATE_LIMITS so that it is always
invoked when a target frequency update is requested.

Link: https://lore.kernel.org/linux-pm/20250619000925.415528-3-pmalani@google.com/ [1]
Suggested-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Prashant Malani &lt;pmalani@google.com&gt;
Acked-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
Link: https://patch.msgid.link/20250722055611.130574-2-pmalani@google.com
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PM: cpufreq: powernv/tracing: Move powernv_throttle trace event</title>
<updated>2025-08-15T14:38:50+00:00</updated>
<author>
<name>Steven Rostedt</name>
<email>rostedt@goodmis.org</email>
</author>
<published>2025-06-12T14:53:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2ac8507d90ea881ef125638aea4a86bd5c9e99b1'/>
<id>2ac8507d90ea881ef125638aea4a86bd5c9e99b1</id>
<content type='text'>
[ Upstream commit 647fe16b46999258ce1aec41f4bdeabb4f0cc8e7 ]

As the trace event powernv_throttle is only used by the powernv code, move
it to a separate include file and have that code directly enable it.

Trace events can take up around 5K of memory when they are defined
regardless if they are used or not. It wastes memory to have them defined
in configurations where the tracepoint is not used.

Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Mathieu Desnoyers &lt;mathieu.desnoyers@efficios.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/20250612145407.906308844@goodmis.org
Fixes: 0306e481d479a ("cpufreq: powernv/tracing: Add powernv_throttle tracepoint")
Acked-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
Acked-by: Rafael J. Wysocki &lt;rafael@kernel.org&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 647fe16b46999258ce1aec41f4bdeabb4f0cc8e7 ]

As the trace event powernv_throttle is only used by the powernv code, move
it to a separate include file and have that code directly enable it.

Trace events can take up around 5K of memory when they are defined
regardless if they are used or not. It wastes memory to have them defined
in configurations where the tracepoint is not used.

Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Mathieu Desnoyers &lt;mathieu.desnoyers@efficios.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: Madhavan Srinivasan &lt;maddy@linux.ibm.com&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Link: https://lore.kernel.org/20250612145407.906308844@goodmis.org
Fixes: 0306e481d479a ("cpufreq: powernv/tracing: Add powernv_throttle tracepoint")
Acked-by: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
Acked-by: Rafael J. Wysocki &lt;rafael@kernel.org&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>cpufreq: Init policy-&gt;rwsem before it may be possibly used</title>
<updated>2025-08-15T14:38:34+00:00</updated>
<author>
<name>Lifeng Zheng</name>
<email>zhenglifeng1@huawei.com</email>
</author>
<published>2025-07-09T10:41:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=84fb57341630fbbf1650fffcd8b542baa60cc1a7'/>
<id>84fb57341630fbbf1650fffcd8b542baa60cc1a7</id>
<content type='text'>
[ Upstream commit d1378d1d7edb3a4c4935a44fe834ae135be03564 ]

In cpufreq_policy_put_kobj(), policy-&gt;rwsem is used. But in
cpufreq_policy_alloc(), if freq_qos_add_notifier() returns an error, error
path via err_kobj_remove or err_min_qos_notifier will be reached and
cpufreq_policy_put_kobj() will be called before policy-&gt;rwsem is
initialized. Thus, the calling of init_rwsem() should be moved to where
before these two error paths can be reached.

Fixes: 67d874c3b2c6 ("cpufreq: Register notifiers with the PM QoS framework")
Signed-off-by: Lifeng Zheng &lt;zhenglifeng1@huawei.com&gt;
Link: https://patch.msgid.link/20250709104145.2348017-3-zhenglifeng1@huawei.com
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit d1378d1d7edb3a4c4935a44fe834ae135be03564 ]

In cpufreq_policy_put_kobj(), policy-&gt;rwsem is used. But in
cpufreq_policy_alloc(), if freq_qos_add_notifier() returns an error, error
path via err_kobj_remove or err_min_qos_notifier will be reached and
cpufreq_policy_put_kobj() will be called before policy-&gt;rwsem is
initialized. Thus, the calling of init_rwsem() should be moved to where
before these two error paths can be reached.

Fixes: 67d874c3b2c6 ("cpufreq: Register notifiers with the PM QoS framework")
Signed-off-by: Lifeng Zheng &lt;zhenglifeng1@huawei.com&gt;
Link: https://patch.msgid.link/20250709104145.2348017-3-zhenglifeng1@huawei.com
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
