Fushuai Wang 069ae9502f cpufreq: intel_pstate: Sync policy->cur during CPU offline
commit bcbdaa1086 upstream.

When a CPU goes offline with HWP disabled, intel_pstate_set_min_pstate()
sets the MSR_IA32_PERF_CTL to minimum frequency to prevent SMT siblings
from being restricted. However, the policy->cur value was not updated,
leaving it at the previous value.

When the CPU comes back online, governor->limits() checks if target_freq
equals policy->cur and skips the frequency adjustment if they match. Since
policy->cur still holds the previous value, the governor does not call
cpufreq_driver->target to update MSR_IA32_PERF_CTL.

Fix this by synchronizing policy->cur with the hardware state when setting
minimum pstate during CPU offline.

Fixes: bb18008f80 ("intel_pstate: Set core to min P state during core offline")
Cc: stable@vger.kernel.org # 3.15+
Suggested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Fushuai Wang <wangfushuai@baidu.com>
[ rjw: Subject refinement ]
Link: https://patch.msgid.link/20260520032119.30615-1-fushuai.wang@linux.dev
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-24 16:02:48 +02:00
2026-05-23 13:03:09 +02:00
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2026-05-23 13:03:09 +02:00
2026-07-04 13:42:28 +02:00
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Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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