From: Sumit Gupta Date: Fri, 6 Feb 2026 14:26:58 +0000 (+0530) Subject: cpufreq: CPPC: Add sysfs documentation for perf_limited X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=856250ba2e810e772dc95b3234ebf0d6393a51d9;p=thirdparty%2Flinux.git cpufreq: CPPC: Add sysfs documentation for perf_limited Add ABI documentation for the Performance Limited Register sysfs interface in the cppc_cpufreq driver. Signed-off-by: Sumit Gupta Reviewed-by: Randy Dunlap Reviewed-by: Pierre Gondois Reviewed-by: Lifeng Zheng Link: https://patch.msgid.link/20260206142658.72583-8-sumitg@nvidia.com Signed-off-by: Rafael J. Wysocki --- diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 3a05604c21bf8..82d10d556cc89 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -327,6 +327,24 @@ Description: Energy performance preference This file is only present if the cppc-cpufreq driver is in use. +What: /sys/devices/system/cpu/cpuX/cpufreq/perf_limited +Date: February 2026 +Contact: linux-pm@vger.kernel.org +Description: Performance Limited + + Read to check if platform throttling (thermal/power/current + limits) caused delivered performance to fall below the + requested level. A non-zero value indicates throttling occurred. + + Write the bitmask of bits to clear: + + - 0x1 = clear bit 0 (desired performance excursion) + - 0x2 = clear bit 1 (minimum performance excursion) + - 0x3 = clear both bits + + The platform sets these bits; OSPM can only clear them. + + 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