[PATCH v2] cpupower: Implement powercap_set_enabled()

Suchit Karunakaran
2025-05-20T09:43:58Z

The powercap_set_enabled() function previously returned a dummy value
and was marked with a TODO comment to implement it. This patch implements the
function by writing the desired mode (0 or 1) to /sys/class/powercap/intel-rapl/enabled

Signed-off-by: Suchit Karunakaran <suchitkarunakaran@gmail.com>
---
tools/power/cpupower/lib/powercap.c | 22 ++++++++++++++++++----
1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/tools/power/cpupower/lib/powercap.c b/tools/power/cpupower/lib/powercap.c
index 94a0c69e55ef..7947b9809239 100644
--- a/tools/power/cpupower/lib/powercap.c
+++ b/tools/power/cpupower/lib/powercap.c
@@ -70,6 +70,22 @@ static int sysfs_get_enabled(char *path, int *mode)
return ret;
}

+static int sysfs_set_enabled(const char *path, int mode)
+{
+ int fd;
+ char buf[2] = { mode ? '1' : '0', '\n' };
+ ssize_t ret;
+
+ fd = open(path, O_WRONLY);
+ if (fd == -1)
+ return -1;
+
+ ret = write(fd, buf, sizeof(buf));
+ close(fd);
+
+ return ret == sizeof(buf) ? 0 : -1;
+}
+
int powercap_get_enabled(int *mode)
{
char path[SYSFS_PATH_MAX] = PATH_TO_POWERCAP "/intel-rapl/enabled";
@@ -77,12 +93,10 @@ 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;
+ char path[SYSFS_PATH_MAX] = PATH_TO_POWERCAP "/intel-rapl/enabled";
+ return sysfs_set_enabled(path, mode);
}

/*
--
2.49.0