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path: root/drivers/cpuidle/cpuidle-powernv.c
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Diffstat (limited to 'drivers/cpuidle/cpuidle-powernv.c')
-rw-r--r--drivers/cpuidle/cpuidle-powernv.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
index 370593006f5f..cda8f62d555b 100644
--- a/drivers/cpuidle/cpuidle-powernv.c
+++ b/drivers/cpuidle/cpuidle-powernv.c
@@ -175,6 +175,24 @@ static int powernv_cpuidle_driver_init(void)
drv->state_count += 1;
}
+ /*
+ * On the PowerNV platform cpu_present may be less than cpu_possible in
+ * cases when firmware detects the CPU, but it is not available to the
+ * OS. If CONFIG_HOTPLUG_CPU=n, then such CPUs are not hotplugable at
+ * run time and hence cpu_devices are not created for those CPUs by the
+ * generic topology_init().
+ *
+ * drv->cpumask defaults to cpu_possible_mask in
+ * __cpuidle_driver_init(). This breaks cpuidle on PowerNV where
+ * cpu_devices are not created for CPUs in cpu_possible_mask that
+ * cannot be hot-added later at run time.
+ *
+ * Trying cpuidle_register_device() on a CPU without a cpu_device is
+ * incorrect, so pass a correct CPU mask to the generic cpuidle driver.
+ */
+
+ drv->cpumask = (struct cpumask *)cpu_present_mask;
+
return 0;
}