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authorVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>2008-05-19 19:09:27 -0400
committerLen Brown <len.brown@intel.com>2008-06-11 19:13:45 -0400
commitdcb84f335bee9c9a7781cfc5d74492dccaf066d2 (patch)
treee24d4ca7df49b2a87862aa69c09d21ad45a024b7 /drivers/cpuidle/cpuidle.c
parente1094bfa26e5e94af2fea79e004614dbce42b008 (diff)
cpuidle acpi driver: fix oops on AC<->DC
cpuidle and acpi driver interaction bug with the way cpuidle_register_driver() is called. Due to this bug, there will be oops on AC<->DC on some systems, where they support C-states in one DC and not in AC. The current code does ON BOOT: Look at CST and other C-state info to see whether more than C1 is supported. If it is, then acpi processor_idle does a cpuidle_register_driver() call, which internally enables the device. ON CST change notification (AC<->DC) and on suspend-resume: acpi driver temporarily disables device, updates the device with any new C-states, and reenables the device. The problem is is on boot, there are no C2, C3 states supported and we skip the register. Later on AC<->DC, we may get a CST notification and we try to reevaluate CST and enabled the device, without actually registering it. This causes breakage as we try to create /sys fs sub directory, without the parent directory which is created at register time. Thanks to Sanjeev for reporting the problem here. http://bugzilla.kernel.org/show_bug.cgi?id=10394 Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/cpuidle/cpuidle.c')
-rw-r--r--drivers/cpuidle/cpuidle.c40
1 files changed, 35 insertions, 5 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index fc555a90bb21..23554b676d6e 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -38,6 +38,8 @@ static void cpuidle_kick_cpus(void)
38static void cpuidle_kick_cpus(void) {} 38static void cpuidle_kick_cpus(void) {}
39#endif 39#endif
40 40
41static int __cpuidle_register_device(struct cpuidle_device *dev);
42
41/** 43/**
42 * cpuidle_idle_call - the main idle loop 44 * cpuidle_idle_call - the main idle loop
43 * 45 *
@@ -138,6 +140,12 @@ int cpuidle_enable_device(struct cpuidle_device *dev)
138 if (!dev->state_count) 140 if (!dev->state_count)
139 return -EINVAL; 141 return -EINVAL;
140 142
143 if (dev->registered == 0) {
144 ret = __cpuidle_register_device(dev);
145 if (ret)
146 return ret;
147 }
148
141 if ((ret = cpuidle_add_state_sysfs(dev))) 149 if ((ret = cpuidle_add_state_sysfs(dev)))
142 return ret; 150 return ret;
143 151
@@ -232,10 +240,13 @@ static void poll_idle_init(struct cpuidle_device *dev) {}
232#endif /* CONFIG_ARCH_HAS_CPU_RELAX */ 240#endif /* CONFIG_ARCH_HAS_CPU_RELAX */
233 241
234/** 242/**
235 * cpuidle_register_device - registers a CPU's idle PM feature 243 * __cpuidle_register_device - internal register function called before register
244 * and enable routines
236 * @dev: the cpu 245 * @dev: the cpu
246 *
247 * cpuidle_lock mutex must be held before this is called
237 */ 248 */
238int cpuidle_register_device(struct cpuidle_device *dev) 249static int __cpuidle_register_device(struct cpuidle_device *dev)
239{ 250{
240 int ret; 251 int ret;
241 struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu); 252 struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu);
@@ -247,18 +258,34 @@ int cpuidle_register_device(struct cpuidle_device *dev)
247 258
248 init_completion(&dev->kobj_unregister); 259 init_completion(&dev->kobj_unregister);
249 260
250 mutex_lock(&cpuidle_lock);
251
252 poll_idle_init(dev); 261 poll_idle_init(dev);
253 262
254 per_cpu(cpuidle_devices, dev->cpu) = dev; 263 per_cpu(cpuidle_devices, dev->cpu) = dev;
255 list_add(&dev->device_list, &cpuidle_detected_devices); 264 list_add(&dev->device_list, &cpuidle_detected_devices);
256 if ((ret = cpuidle_add_sysfs(sys_dev))) { 265 if ((ret = cpuidle_add_sysfs(sys_dev))) {
257 mutex_unlock(&cpuidle_lock);
258 module_put(cpuidle_curr_driver->owner); 266 module_put(cpuidle_curr_driver->owner);
259 return ret; 267 return ret;
260 } 268 }
261 269
270 dev->registered = 1;
271 return 0;
272}
273
274/**
275 * cpuidle_register_device - registers a CPU's idle PM feature
276 * @dev: the cpu
277 */
278int cpuidle_register_device(struct cpuidle_device *dev)
279{
280 int ret;
281
282 mutex_lock(&cpuidle_lock);
283
284 if ((ret = __cpuidle_register_device(dev))) {
285 mutex_unlock(&cpuidle_lock);
286 return ret;
287 }
288
262 cpuidle_enable_device(dev); 289 cpuidle_enable_device(dev);
263 cpuidle_install_idle_handler(); 290 cpuidle_install_idle_handler();
264 291
@@ -278,6 +305,9 @@ void cpuidle_unregister_device(struct cpuidle_device *dev)
278{ 305{
279 struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu); 306 struct sys_device *sys_dev = get_cpu_sysdev((unsigned long)dev->cpu);
280 307
308 if (dev->registered == 0)
309 return;
310
281 cpuidle_pause_and_lock(); 311 cpuidle_pause_and_lock();
282 312
283 cpuidle_disable_device(dev); 313 cpuidle_disable_device(dev);