From: Venki Pallipadi <venkatesh.pallipadi@xxxxxxxxx>
Prevent hang on x86-64, when ACPI processor driver is added as a module on
a system that does not support C-states.
x86-64 expects all idle handlers to enable interrupts before returning from
idle handler. This is due to enter_idle(), exit_idle() races. Make
cpuidle_idle_call() confirm to this when there is no pm_idle_old.
Also, cpuidle look at the return values of attch_driver() and set
current_driver to NULL if attach fails on all CPUs.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/cpuidle/cpuidle.c | 2 ++
drivers/cpuidle/driver.c | 15 ++++++++++++---
2 files changed, 14 insertions(+), 3 deletions(-)
diff -puN drivers/cpuidle/cpuidle.c~cpuidle-hang-fix drivers/cpuidle/cpuidle.c
--- a/drivers/cpuidle/cpuidle.c~cpuidle-hang-fix
+++ a/drivers/cpuidle/cpuidle.c
@@ -43,6 +43,8 @@ static void cpuidle_idle_call(void)
if (dev->status != CPUIDLE_STATUS_DOIDLE) {
if (pm_idle_old)
pm_idle_old();
+ else
+ local_irq_enable();
return;
}
diff -puN drivers/cpuidle/driver.c~cpuidle-hang-fix drivers/cpuidle/driver.c
--- a/drivers/cpuidle/driver.c~cpuidle-hang-fix
+++ a/drivers/cpuidle/driver.c
@@ -107,11 +107,20 @@ int cpuidle_switch_driver(struct cpuidle
cpuidle_curr_driver = drv;
if (drv) {
+ int ret = 1;
list_for_each_entry(dev, &cpuidle_detected_devices, device_list)
- cpuidle_attach_driver(dev);
- if (cpuidle_curr_governor)
+ if (cpuidle_attach_driver(dev) == 0)
+ ret = 0;
+
+ /* If attach on all devices fail, switch to NULL driver */
+ if (ret)
+ cpuidle_curr_driver = NULL;
+
+ if (cpuidle_curr_driver && cpuidle_curr_governor) {
+ printk(KERN_INFO "cpuidle: using driver %s\n",
+ drv->name);
cpuidle_install_idle_handler();
- printk(KERN_INFO "cpuidle: using driver %s\n", drv->name);
+ }
}
return 0;
_
-
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