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Filename Latest commit message Latest commit date
Jiayi Li bd844a24e5 ACPI: processor: perflib: Fix initial _PPC limit application
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: d15ce41273 ("ACPI: cpufreq: Switch to QoS requests instead of cpufreq notifier")
Signed-off-by: Jiayi Li <lijiayi@kylinos.cn>
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+ <stable@vger.kernel.org> # 5.4+: 2d8b39a62a ACPI: processor: Avoid NULL pointer dereferences at init time
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+: 3000ce3c52 cpufreq: Use per-policy frequency QoS
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+: a1bb46c36c ACPI: processor: Add QoS requests for all CPUs
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-08-28 16:21:23 +02:00
arch MIPS: mm: tlb-r4k: Uniquify TLB entries on init 2025-08-28 16:21:23 +02:00
block block: fix 'kmem_cache of name 'bio-108' already exists' 2025-04-10 14:29:37 +02:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:11:22 +02:00
crypto crypto: algif_hash - fix double free in hash_accept 2025-06-04 14:32:35 +02:00
Documentation Documentation: ACPI: Fix parent device references 2025-08-28 16:21:23 +02:00
drivers ACPI: processor: perflib: Fix initial _PPC limit application 2025-08-28 16:21:23 +02:00
fs fs: Prevent file descriptor table allocations exceeding INT_MAX 2025-08-28 16:21:23 +02:00
include io_uring: don't use int for ABI 2025-08-28 16:21:23 +02:00
init bpfilter: match bit size of bpfilter_umh to that of the kernel 2025-07-17 18:24:51 +02:00
ipc ipc: fix to protect IPCS lookups using RCU 2025-06-27 11:02:52 +01:00
kernel perf/core: Prevent VMA split of buffer mappings 2025-08-28 16:21:23 +02:00
lib lib: test_objagg: Set error message in check_expect_hints_stats() 2025-07-17 18:24:56 +02:00
LICENSES
mm mm/huge_memory: fix dereferencing invalid pmd migration entry 2025-06-27 11:02:58 +01:00
net netlink: avoid infinite retry looping in netlink_unicast() 2025-08-28 16:21:23 +02:00
samples samples: mei: Fix building on musl libc 2025-08-28 16:21:19 +02:00
scripts kbuild: use -MMD instead of -MD to exclude system headers from dependency 2025-07-17 18:24:51 +02:00
security selinux: fix selinux_xfrm_alloc_user() to set correct ctx_len 2025-06-27 11:02:56 +01:00
sound ALSA: usb-audio: Validate UAC3 cluster segment descriptors 2025-08-28 16:21:23 +02:00
tools perf tests bp_account: Fix leaked file descriptor 2025-08-28 16:21:20 +02:00
usr kbuild: hdrcheck: fix cross build with clang 2025-07-17 18:24:51 +02:00
virt KVM: arm64: Ignore PMCNTENSET_EL0 while checking for overflow status 2024-12-19 18:05:04 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Remove *.orig pattern from .gitignore 2024-11-08 16:20:33 +01:00
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS platform: Add Surface platform directory 2025-06-27 11:02:56 +01:00
Makefile Linux 5.4.296 2025-07-17 18:25:06 +02:00
README

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.