x86: get the MWAIT idle driver in sync with the ACPI one

.. with respect to behavior when there is no HPET broadcast support
(for using the PIT broadcast instead, it requires explicitly enabling
CPU idle management).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>

diff --git a/xen/arch/x86/cpu/mwait-idle.c b/xen/arch/x86/cpu/mwait-idle.c
index 6a9ca95d33b36c52d54ec4fce54ffa91ffe6d070..f8bbf0f2314b784b1de4accb19bf3e14cdbee068 100644 (file)
--- a/xen/arch/x86/cpu/mwait-idle.c
+++ b/xen/arch/x86/cpu/mwait-idle.c
@@ -501,11 +501,14 @@ int __init mwait_idle_init(struct notifier_block *nfb)
                return -ENODEV;
 
        err = mwait_idle_probe();
-       if (!err) {
-               if (!boot_cpu_has(X86_FEATURE_ARAT))
-                       hpet_broadcast_init();
-               if (!lapic_timer_init())
+       if (!err && !boot_cpu_has(X86_FEATURE_ARAT)) {
+               hpet_broadcast_init();
+               if (xen_cpuidle < 0 && !hpet_broadcast_is_available())
+                       err = -ENODEV;
+               else if(!lapic_timer_init())
                        err = -EINVAL;
+               if (err)
+                       pr_debug(PREFIX "not used (%d)\n", err);
        }
        if (!err) {
                nfb->notifier_call = mwait_idle_cpu_init;