[PATCH v3 6/8] cpufreq: CPPC: Add sysfs for min/max_perf and perf_limited
From: Sumit Gupta <sumitg@nvidia.com>
Date: 2025-10-01 15:02:48
Also in:
linux-acpi, linux-pm, linux-tegra, lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
Add sysfs interfaces for Minimum Performance, Maximum Performance and Performance Limited Register in the cppc_cpufreq driver. Reviewed-by: Randy Dunlap <redacted> Signed-off-by: Sumit Gupta <sumitg@nvidia.com> --- .../ABI/testing/sysfs-devices-system-cpu | 43 +++++++++++++++++++ 1 file changed, 43 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index ab8cd337f43a..82141b45d58c 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu@@ -327,6 +327,49 @@ Description: Energy performance preference This file is only present if the cppc-cpufreq driver is in use. +What: /sys/devices/system/cpu/cpuX/cpufreq/min_perf +Date: September 2025 +Contact: linux-pm@vger.kernel.org +Description: Minimum Performance + + Read/write a 32 bits value from/to this file. This file + conveys the minimum performance level at which the platform + may run. Minimum performance may be set to any performance + value in the range [Lowest Performance, Highest Performance], + inclusive but must be set to a value that is less than or + equal to that specified by the Maximum Performance Register. + + Writing to this file only has meaning when Autonomous Selection + is enabled. + + This file is only present if the cppc-cpufreq driver is in use. + +What: /sys/devices/system/cpu/cpuX/cpufreq/max_perf +Date: September 2025 +Contact: linux-pm@vger.kernel.org +Description: Minimum Performance + + Read/write a 32 bits value from/to this file. This file conveys + the maximum performance level at which the platform may run. + Maximum performance may be set to any performance value in the + range [Lowest Performance, Highest Performance], inclusive. + + Writing to this file only has meaning when Autonomous Selection is + enabled. + + This file is only present if the cppc-cpufreq driver is in use. + +What: /sys/devices/system/cpu/cpuX/cpufreq/perf_limited +Date: September 2025 +Contact: linux-pm@vger.kernel.org +Description: Minimum Performance + + Read/write a 32 bits value from/to this file. This file indicates + to OSPM that an unpredictable event has limited processor + performance, and the delivered performance may be less than + desired/minimum performance. + + This file is only present if the cppc-cpufreq driver is in use. What: /sys/devices/system/cpu/cpu*/cache/index3/cache_disable_{0,1} Date: August 2008
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2.34.1