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[31.183.167.127]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-bcac3a8063dsm143968066b.41.2026.05.08.15.35.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 08 May 2026 15:35:30 -0700 (PDT) From: =?UTF-8?q?Mateusz=20Ja=C5=9Bkiewicz?= To: Thomas Renninger , Shuah Khan , "John B . Wyatt IV" , John Kacur Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, =?UTF-8?q?Mateusz=20Ja=C5=9Bkiewicz?= Subject: [PATCH] cpupower: Implement powercap enabled setters Date: Sat, 9 May 2026 00:35:24 +0200 Message-ID: <20260508223524.1314573-1-jaskiewiczteo@gmail.com> X-Mailer: git-send-email 2.54.0 Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit powercap_set_enabled() and powercap_zone_set_enabled() are part of the public libcpupower API, but both currently return success without updating sysfs. Write the requested value to the matching enabled attribute so callers can actually enable or disable the powercap control type or zone, and report write failures back to the caller. Signed-off-by: Mateusz Jaśkiewicz --- tools/power/cpupower/lib/powercap.c | 43 +++++++++++++++++++++++------ 1 file changed, 35 insertions(+), 8 deletions(-) diff --git a/tools/power/cpupower/lib/powercap.c b/tools/power/cpupower/lib/powercap.c index 94a0c69e5..6d8b83428 100644 --- a/tools/power/cpupower/lib/powercap.c +++ b/tools/power/cpupower/lib/powercap.c @@ -70,6 +70,27 @@ static int sysfs_get_enabled(char *path, int *mode) return ret; } +static int sysfs_set_enabled(const char *path, int mode) +{ + char yes_no; + int fd; + ssize_t ret; + + if (mode != 0 && mode != 1) + return -1; + + yes_no = mode ? '1' : '0'; + fd = open(path, O_WRONLY); + if (-1 == fd) + return -1; + ret = write(fd, &yes_no, 1); + if (ret != 1) { + close(fd); + return -1; + } + return close(fd); +} + int powercap_get_enabled(int *mode) { char path[SYSFS_PATH_MAX] = PATH_TO_POWERCAP "/intel-rapl/enabled"; @@ -77,17 +98,13 @@ int powercap_get_enabled(int *mode) return sysfs_get_enabled(path, mode); } -/* - * TODO: implement function. Returns dummy 0 for now. - */ int powercap_set_enabled(int mode) { - return 0; + return sysfs_set_enabled(PATH_TO_RAPL "/enabled", mode); } - /* * Hardcoded, because rapl is the only powercap implementation -- * this needs to get more generic if more powercap implementations + * this needs to get more generic if more powercap implementations * should show up */ int powercap_get_driver(char *driver, int buflen) @@ -180,8 +197,18 @@ int powercap_zone_get_enabled(struct powercap_zone *zone, int *mode) int powercap_zone_set_enabled(struct powercap_zone *zone, int mode) { - /* To be done if needed */ - return 0; + char path[SYSFS_PATH_MAX]; + int ret; + + if (!zone) + return -1; + + ret = snprintf(path, sizeof(path), "%s/%s/enabled", + PATH_TO_POWERCAP, zone->sys_name); + if (ret < 0 || ret >= (int)sizeof(path)) + return -1; + + return sysfs_set_enabled(path, mode); } -- 2.54.0