power: fix error handling on setting governor

In the power_set_governor_*() functions, we using fputs() on /sys
filesystem. However, we also need to call fflush() to ensure that
the write completes successfully. Otherwise the attempt to set the
power governor fails and the function returns as if it has
succeeded. This patch adds an fflush to ensure that the
write succeeds, otherwise returns an error.

Fixes: e6c6dc0f96c8 ("power: add p-state driver compatibility")
Signed-off-by: David Hunt <david.hunt@intel.com>

diff --git a/lib/librte_power/power_acpi_cpufreq.c b/lib/librte_power/power_acpi_cpufreq.c
index cd5978d5b312c831ec55a4bb2a5efc337e9e12ef..f50897b4dd6056fb090fed8a7899d91d0fd3e1eb 100644 (file)
--- a/lib/librte_power/power_acpi_cpufreq.c
+++ b/lib/librte_power/power_acpi_cpufreq.c
@@ -166,6 +166,10 @@ power_set_governor_userspace(struct rte_power_info *pi)
        val = fputs(POWER_GOVERNOR_USERSPACE, f);
        FOPS_OR_ERR_GOTO(val, out);
 
+       /* We need to flush to see if the fputs succeeds */
+       val = fflush(f);
+       FOPS_OR_ERR_GOTO(val, out);
+
        ret = 0;
        RTE_LOG(INFO, POWER, "Power management governor of lcore %u has been "
                        "set to user space successfully\n", pi->lcore_id);

diff --git a/lib/librte_power/power_pstate_cpufreq.c b/lib/librte_power/power_pstate_cpufreq.c
index 411d0eb163d207b5bb079db8ce8e437b9fc76a2d..0f8e8f9706b53443f8e352b71ea4f045eb9beb27 100644 (file)
--- a/lib/librte_power/power_pstate_cpufreq.c
+++ b/lib/librte_power/power_pstate_cpufreq.c
@@ -308,6 +308,10 @@ power_set_governor_performance(struct pstate_power_info *pi)
        val = fputs(POWER_GOVERNOR_PERF, f);
        FOPS_OR_ERR_GOTO(val, out);
 
+       /* We need to flush to see if the fputs succeeds */
+       val = fflush(f);
+       FOPS_OR_ERR_GOTO(val, out);
+
        ret = 0;
        RTE_LOG(INFO, POWER, "Power management governor of lcore %u has been "
                        "set to performance successfully\n", pi->lcore_id);