thermal: cpufreq_cooling: freq_qos_update_request() returns < 0 on error

freq_qos_update_request() returns 1 if the effective constraint value
has changed, 0 if the effective constraint value has not changed, or a
negative error code on failures.

The frequency constraints for CPUs can be set by different parts of the
kernel. If the maximum frequency constraint set by other parts of the
kernel are set at a lower value than the one corresponding to cooling
state 0, then we will never be able to cool down the system as
freq_qos_update_request() will keep on returning 0 and we will skip
updating cpufreq_state and thermal pressure.

Fix that by doing the updates even in the case where
freq_qos_update_request() returns 0, as we have effectively set the
constraint to a new value even if the consolidated value of the
actual constraint is unchanged because of external factors.

Cc: v5.7+ <stable@vger.kernel.org> # v5.7+
Reported-by: Thara Gopinath <thara.gopinath@linaro.org>
Fixes: f12e4f66ab6a ("thermal/cpu-cooling: Update thermal pressure in case of a maximum frequency capping")
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Tested-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Thara Gopinath<thara.gopinath@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/b2b7e84944937390256669df5a48ce5abba0c1ef.1613540713.git.viresh.kumar@linaro.org

diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c
index 612f063c1cfcd49b5cb6eb67948a774ac2cc62d3..ddc166e3a93eb04d4b08b2ef504c7a97d3fac905 100644 (file)
--- a/drivers/thermal/cpufreq_cooling.c
+++ b/drivers/thermal/cpufreq_cooling.c
@@ -441,7 +441,7 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
        frequency = get_state_freq(cpufreq_cdev, state);
 
        ret = freq_qos_update_request(&cpufreq_cdev->qos_req, frequency);
-       if (ret > 0) {
+       if (ret >= 0) {
                cpufreq_cdev->cpufreq_state = state;
                cpus = cpufreq_cdev->policy->cpus;
                max_capacity = arch_scale_cpu_capacity(cpumask_first(cpus));