Lukasz Luba writes:
+/**
+ * em_dev_unregister_perf_domain() - Unregister Energy Model
(EM) for a device
+ * @dev : Device for which the EM is registered
+ *
+ * Try to unregister the EM for the specified device (it checks
current
+ * reference counter). The EM for CPUs will not be freed.
+ */
+void em_dev_unregister_perf_domain(struct device *dev)
+{
+ struct em_device *em_dev, *tmp;
+
+ if (IS_ERR_OR_NULL(dev))
+ return;
+
+ /* We don't support freeing CPU structures in hotplug */
+ if (_is_cpu_device(dev)) {
+ dev_dbg_once(dev, "EM: the structures are not going to be
removed\n");
+ return;
+ }
+
+ mutex_lock(&em_pd_mutex);
+
+ if (list_empty(&em_pd_dev_list)) {
+ mutex_unlock(&em_pd_mutex);
+ return;
+ }
+
+ list_for_each_entry_safe(em_dev, tmp, &em_pd_dev_list,
em_dev_list) {
+ if (em_dev->dev == dev) {
+ kref_put(&em_dev->kref, _em_release);
+ break;
+ }
+ }
+
+ mutex_unlock(&em_pd_mutex);
+}
+EXPORT_SYMBOL_GPL(em_dev_unregister_perf_domain);
Ok, so em_dev_unregister_perf_domain() does not support the CPU
device
and a subsequent em_register_perf_domain() will fail with EEXIST.
Is there a way to unregister/change the CPU's energy model during
runtime without restarting the whole system?
