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| author | Jiayi Li <lijiayi@kylinos.cn> | 2025-07-21 11:26:06 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-08-28 16:25:49 +0200 |
| commit | 81314c7f1ff0b4b942d87bff6a87f3a2faf7ab5f (patch) | |
| tree | 235e0563ded1848342802097e0f82901e7167882 /drivers/acpi | |
| parent | cfeaebc3554005ca3b1915a729200d0ecccb1714 (diff) | |
| download | linux-81314c7f1ff0b4b942d87bff6a87f3a2faf7ab5f.tar.gz linux-81314c7f1ff0b4b942d87bff6a87f3a2faf7ab5f.tar.bz2 linux-81314c7f1ff0b4b942d87bff6a87f3a2faf7ab5f.zip | |
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: d15ce412737a ("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+: 2d8b39a62a5d ACPI: processor: Avoid NULL pointer dereferences at init time
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+: 3000ce3c52f8 cpufreq: Use per-policy frequency QoS
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+: a1bb46c36ce3 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>
Diffstat (limited to 'drivers/acpi')
| -rw-r--r-- | drivers/acpi/processor_perflib.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c index 1696700fd2fb..f23c55350bb4 100644 --- a/drivers/acpi/processor_perflib.c +++ b/drivers/acpi/processor_perflib.c @@ -173,11 +173,14 @@ void acpi_processor_ppc_init(struct cpufreq_policy *policy) { unsigned int cpu; + if (ignore_ppc == 1) + return; + for_each_cpu(cpu, policy->related_cpus) { struct acpi_processor *pr = per_cpu(processors, cpu); int ret; - if (!pr) + if (!pr || !pr->performance) continue; /* @@ -193,6 +196,11 @@ void acpi_processor_ppc_init(struct cpufreq_policy *policy) if (ret < 0) pr_err("Failed to add freq constraint for CPU%d (%d)\n", cpu, ret); + + ret = acpi_processor_get_platform_limit(pr); + if (ret) + pr_err("Failed to update freq constraint for CPU%d (%d)\n", + cpu, ret); } } |