diff mbox series

[v1,2/3] ACPI: PM: Fix sharing of wakeup power resources

Message ID 2077987.irdbgypaU6@kreacher (mailing list archive)
State New, archived
Delegated to: Bjorn Helgaas
Headers show
Series ACPI: PM: Address issues related to managing wakeup power resources | expand

Commit Message

Rafael J. Wysocki Oct. 15, 2021, 5:03 p.m. UTC 
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

If an ACPI wakeup power resource is shared between multiple devices,
it may not be managed correctly.

Suppose, for example, that two devices, A and B, share a wakeup power
resource P whose wakeup_enabled flag is 0 initially.  Next, suppose
that wakeup power is enabled for A and B, in this order, and disabled
for B.  When wakeup power is enabled for A, P will be turned on and
its wakeup_enabled flag will be set.  Next, when wakeup power is
enabled for B, P will not be touched, because its wakeup_enabled flag
is set.  Now, when wakeup power is disabled for B, P will be turned
off which is incorrect, because A will still need P in order to signal
wakeup.

Moreover, if wakeup power is enabled for A and then disabled for B,
the latter will cause P to be turned off incorrectly (it will be still
needed by A), because acpi_disable_wakeup_device_power() is allowed
to manipulate power resources when the wakeup.prepare_count counter
of the given device is 0.

While the first issue could be addressed by changing the
wakeup_enabled power resource flag into a counter, addressing the
second one requires modifying acpi_disable_wakeup_device_power() to
do nothing when the target device's wakeup.prepare_count reference
counter is zero and that would cause the new counter to be redundant.
Namely, if acpi_disable_wakeup_device_power() is modified as per the
above, every change of the new counter following a wakeup.prepare_count
change would be reflected by the analogous change of the main reference
counter of the given power resource.

Accordingly, modify acpi_disable_wakeup_device_power() to do nothing
when the target device's wakeup.prepare_count reference counter is
zero and drop the power resource wakeup_enabled flag altogether.

While at it, ensure that all of the power resources that can be
turned off will be turned off when disabling device wakeup due to
a power resource manipulation error, to prevent energy from being
wasted.

Fixes: b5d667eb392e ("ACPI / PM: Take unusual configurations of power resources into account")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/power.c |   73 ++++++++++++++++++---------------------------------
 1 file changed, 26 insertions(+), 47 deletions(-)

Comments

kernel test robot Oct. 15, 2021, 8:31 p.m. UTC | #1 
Hi "Rafael,

I love your patch! Perhaps something to improve:

[auto build test WARNING on rafael-pm/linux-next]
[also build test WARNING on linux/master linus/master v5.15-rc5 next-20211015]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Rafael-J-Wysocki/ACPI-PM-Address-issues-related-to-managing-wakeup-power-resources/20211016-010527
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
config: i386-randconfig-r035-20211015 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 6069a6a5049497a32a50a49661c2f4169078bdba)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/5e93f177b80cbc9b9ee6ffc15ff9ad0ad23f2a7a
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Rafael-J-Wysocki/ACPI-PM-Address-issues-related-to-managing-wakeup-power-resources/20211016-010527
        git checkout 5e93f177b80cbc9b9ee6ffc15ff9ad0ad23f2a7a
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=i386 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/acpi/power.c:719:6: warning: variable 'err' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
           if (dev->wakeup.prepare_count++)
               ^~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/acpi/power.c:739:9: note: uninitialized use occurs here
           return err;
                  ^~~
   drivers/acpi/power.c:719:2: note: remove the 'if' if its condition is always false
           if (dev->wakeup.prepare_count++)
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/acpi/power.c:712:9: note: initialize the variable 'err' to silence this warning
           int err;
                  ^
                   = 0
   drivers/acpi/power.c:764:6: warning: variable 'err' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
           if (!dev->wakeup.prepare_count)
               ^~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/acpi/power.c:789:9: note: uninitialized use occurs here
           return err;
                  ^~~
   drivers/acpi/power.c:764:2: note: remove the 'if' if its condition is always false
           if (!dev->wakeup.prepare_count)
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/acpi/power.c:758:6: warning: variable 'err' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
           if (dev->wakeup.prepare_count > 1) {
               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/acpi/power.c:789:9: note: uninitialized use occurs here
           return err;
                  ^~~
   drivers/acpi/power.c:758:2: note: remove the 'if' if its condition is always false
           if (dev->wakeup.prepare_count > 1) {
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/acpi/power.c:751:9: note: initialize the variable 'err' to silence this warning
           int err;
                  ^
                   = 0
   3 warnings generated.


vim +719 drivers/acpi/power.c

77e766099efc29 Rafael J. Wysocki 2008-07-07  703  
^1da177e4c3f41 Linus Torvalds    2005-04-16  704  /*
^1da177e4c3f41 Linus Torvalds    2005-04-16  705   * Prepare a wakeup device, two steps (Ref ACPI 2.0:P229):
^1da177e4c3f41 Linus Torvalds    2005-04-16  706   * 1. Power on the power resources required for the wakeup device
77e766099efc29 Rafael J. Wysocki 2008-07-07  707   * 2. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
77e766099efc29 Rafael J. Wysocki 2008-07-07  708   *    State Wake) for the device, if present
^1da177e4c3f41 Linus Torvalds    2005-04-16  709   */
77e766099efc29 Rafael J. Wysocki 2008-07-07  710  int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
^1da177e4c3f41 Linus Torvalds    2005-04-16  711  {
5e93f177b80cbc Rafael J. Wysocki 2021-10-15  712  	int err;
^1da177e4c3f41 Linus Torvalds    2005-04-16  713  
^1da177e4c3f41 Linus Torvalds    2005-04-16  714  	if (!dev || !dev->wakeup.flags.valid)
77e766099efc29 Rafael J. Wysocki 2008-07-07  715  		return -EINVAL;
^1da177e4c3f41 Linus Torvalds    2005-04-16  716  
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08  717  	mutex_lock(&acpi_device_lock);
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08  718  
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08 @719  	if (dev->wakeup.prepare_count++)
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08  720  		goto out;
0af4b8c4fb3119 Rafael J. Wysocki 2008-07-07  721  
5e93f177b80cbc Rafael J. Wysocki 2021-10-15  722  	err = acpi_power_on_list(&dev->wakeup.resources);
993cbe595dda73 Rafael J. Wysocki 2013-01-17  723  	if (err) {
5e93f177b80cbc Rafael J. Wysocki 2021-10-15  724  		dev_err(&dev->dev, "Cannot turn on wakeup power resources\n");
^1da177e4c3f41 Linus Torvalds    2005-04-16  725  		dev->wakeup.flags.valid = 0;
b5d667eb392ed9 Rafael J. Wysocki 2013-02-23  726  		goto out;
b5d667eb392ed9 Rafael J. Wysocki 2013-02-23  727  	}
5e93f177b80cbc Rafael J. Wysocki 2021-10-15  728  
77e766099efc29 Rafael J. Wysocki 2008-07-07  729  	/*
993cbe595dda73 Rafael J. Wysocki 2013-01-17  730  	 * Passing 3 as the third argument below means the device may be
993cbe595dda73 Rafael J. Wysocki 2013-01-17  731  	 * put into arbitrary power state afterward.
77e766099efc29 Rafael J. Wysocki 2008-07-07  732  	 */
0af4b8c4fb3119 Rafael J. Wysocki 2008-07-07  733  	err = acpi_device_sleep_wake(dev, 1, sleep_state, 3);
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08  734  	if (err)
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08  735  		dev->wakeup.prepare_count = 0;
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08  736  
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08  737   out:
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08  738  	mutex_unlock(&acpi_device_lock);
0af4b8c4fb3119 Rafael J. Wysocki 2008-07-07  739  	return err;
^1da177e4c3f41 Linus Torvalds    2005-04-16  740  }
^1da177e4c3f41 Linus Torvalds    2005-04-16  741  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
kernel test robot Oct. 19, 2021, 7:25 a.m. UTC | #2 
Hi "Rafael,

I love your patch! Yet something to improve:

[auto build test ERROR on rafael-pm/linux-next]
[also build test ERROR on linux/master linus/master v5.15-rc6 next-20211018]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Rafael-J-Wysocki/ACPI-PM-Address-issues-related-to-managing-wakeup-power-resources/20211016-010527
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
config: i386-buildonly-randconfig-r003-20211019 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project d245f2e8597bfb52c34810a328d42b990e4af1a4)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/5e93f177b80cbc9b9ee6ffc15ff9ad0ad23f2a7a
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Rafael-J-Wysocki/ACPI-PM-Address-issues-related-to-managing-wakeup-power-resources/20211016-010527
        git checkout 5e93f177b80cbc9b9ee6ffc15ff9ad0ad23f2a7a
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=i386 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> drivers/acpi/power.c:719:6: error: variable 'err' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
           if (dev->wakeup.prepare_count++)
               ^~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/acpi/power.c:739:9: note: uninitialized use occurs here
           return err;
                  ^~~
   drivers/acpi/power.c:719:2: note: remove the 'if' if its condition is always false
           if (dev->wakeup.prepare_count++)
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/acpi/power.c:712:9: note: initialize the variable 'err' to silence this warning
           int err;
                  ^
                   = 0
   drivers/acpi/power.c:764:6: error: variable 'err' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
           if (!dev->wakeup.prepare_count)
               ^~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/acpi/power.c:789:9: note: uninitialized use occurs here
           return err;
                  ^~~
   drivers/acpi/power.c:764:2: note: remove the 'if' if its condition is always false
           if (!dev->wakeup.prepare_count)
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/acpi/power.c:758:6: error: variable 'err' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
           if (dev->wakeup.prepare_count > 1) {
               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/acpi/power.c:789:9: note: uninitialized use occurs here
           return err;
                  ^~~
   drivers/acpi/power.c:758:2: note: remove the 'if' if its condition is always false
           if (dev->wakeup.prepare_count > 1) {
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/acpi/power.c:751:9: note: initialize the variable 'err' to silence this warning
           int err;
                  ^
                   = 0
   3 errors generated.


vim +719 drivers/acpi/power.c

77e766099efc29 Rafael J. Wysocki 2008-07-07  703  
^1da177e4c3f41 Linus Torvalds    2005-04-16  704  /*
^1da177e4c3f41 Linus Torvalds    2005-04-16  705   * Prepare a wakeup device, two steps (Ref ACPI 2.0:P229):
^1da177e4c3f41 Linus Torvalds    2005-04-16  706   * 1. Power on the power resources required for the wakeup device
77e766099efc29 Rafael J. Wysocki 2008-07-07  707   * 2. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
77e766099efc29 Rafael J. Wysocki 2008-07-07  708   *    State Wake) for the device, if present
^1da177e4c3f41 Linus Torvalds    2005-04-16  709   */
77e766099efc29 Rafael J. Wysocki 2008-07-07  710  int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
^1da177e4c3f41 Linus Torvalds    2005-04-16  711  {
5e93f177b80cbc Rafael J. Wysocki 2021-10-15  712  	int err;
^1da177e4c3f41 Linus Torvalds    2005-04-16  713  
^1da177e4c3f41 Linus Torvalds    2005-04-16  714  	if (!dev || !dev->wakeup.flags.valid)
77e766099efc29 Rafael J. Wysocki 2008-07-07  715  		return -EINVAL;
^1da177e4c3f41 Linus Torvalds    2005-04-16  716  
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08  717  	mutex_lock(&acpi_device_lock);
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08  718  
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08 @719  	if (dev->wakeup.prepare_count++)
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08  720  		goto out;
0af4b8c4fb3119 Rafael J. Wysocki 2008-07-07  721  
5e93f177b80cbc Rafael J. Wysocki 2021-10-15  722  	err = acpi_power_on_list(&dev->wakeup.resources);
993cbe595dda73 Rafael J. Wysocki 2013-01-17  723  	if (err) {
5e93f177b80cbc Rafael J. Wysocki 2021-10-15  724  		dev_err(&dev->dev, "Cannot turn on wakeup power resources\n");
^1da177e4c3f41 Linus Torvalds    2005-04-16  725  		dev->wakeup.flags.valid = 0;
b5d667eb392ed9 Rafael J. Wysocki 2013-02-23  726  		goto out;
b5d667eb392ed9 Rafael J. Wysocki 2013-02-23  727  	}
5e93f177b80cbc Rafael J. Wysocki 2021-10-15  728  
77e766099efc29 Rafael J. Wysocki 2008-07-07  729  	/*
993cbe595dda73 Rafael J. Wysocki 2013-01-17  730  	 * Passing 3 as the third argument below means the device may be
993cbe595dda73 Rafael J. Wysocki 2013-01-17  731  	 * put into arbitrary power state afterward.
77e766099efc29 Rafael J. Wysocki 2008-07-07  732  	 */
0af4b8c4fb3119 Rafael J. Wysocki 2008-07-07  733  	err = acpi_device_sleep_wake(dev, 1, sleep_state, 3);
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08  734  	if (err)
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08  735  		dev->wakeup.prepare_count = 0;
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08  736  
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08  737   out:
9b83ccd2f14f64 Rafael J. Wysocki 2009-09-08  738  	mutex_unlock(&acpi_device_lock);
0af4b8c4fb3119 Rafael J. Wysocki 2008-07-07  739  	return err;
^1da177e4c3f41 Linus Torvalds    2005-04-16  740  }
^1da177e4c3f41 Linus Torvalds    2005-04-16  741  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff mbox series

Patch

Index: linux-pm/drivers/acpi/power.c
===================================================================
--- linux-pm.orig/drivers/acpi/power.c
+++ linux-pm/drivers/acpi/power.c
@@ -52,7 +52,6 @@  struct acpi_power_resource {
 	u32 order;
 	unsigned int ref_count;
 	u8 state;
-	bool wakeup_enabled;
 	struct mutex resource_lock;
 	struct list_head dependents;
 };
@@ -710,8 +709,7 @@  int acpi_device_sleep_wake(struct acpi_d
  */
 int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
 {
-	struct acpi_power_resource_entry *entry;
-	int err = 0;
+	int err;
 
 	if (!dev || !dev->wakeup.flags.valid)
 		return -EINVAL;
@@ -721,26 +719,13 @@  int acpi_enable_wakeup_device_power(stru
 	if (dev->wakeup.prepare_count++)
 		goto out;
 
-	list_for_each_entry(entry, &dev->wakeup.resources, node) {
-		struct acpi_power_resource *resource = entry->resource;
-
-		mutex_lock(&resource->resource_lock);
-
-		if (!resource->wakeup_enabled) {
-			err = acpi_power_on_unlocked(resource);
-			if (!err)
-				resource->wakeup_enabled = true;
-		}
-
-		mutex_unlock(&resource->resource_lock);
-
-		if (err) {
-			dev_err(&dev->dev,
-				"Cannot turn wakeup power resources on\n");
-			dev->wakeup.flags.valid = 0;
-			goto out;
-		}
+	err = acpi_power_on_list(&dev->wakeup.resources);
+	if (err) {
+		dev_err(&dev->dev, "Cannot turn on wakeup power resources\n");
+		dev->wakeup.flags.valid = 0;
+		goto out;
 	}
+
 	/*
 	 * Passing 3 as the third argument below means the device may be
 	 * put into arbitrary power state afterward.
@@ -763,46 +748,40 @@  int acpi_enable_wakeup_device_power(stru
 int acpi_disable_wakeup_device_power(struct acpi_device *dev)
 {
 	struct acpi_power_resource_entry *entry;
-	int err = 0;
+	int err;
 
 	if (!dev || !dev->wakeup.flags.valid)
 		return -EINVAL;
 
 	mutex_lock(&acpi_device_lock);
 
-	if (--dev->wakeup.prepare_count > 0)
+	if (dev->wakeup.prepare_count > 1) {
+		dev->wakeup.prepare_count--;
 		goto out;
+	}
 
-	/*
-	 * Executing the code below even if prepare_count is already zero when
-	 * the function is called may be useful, for example for initialisation.
-	 */
-	if (dev->wakeup.prepare_count < 0)
-		dev->wakeup.prepare_count = 0;
+	/* Do nothing if wakeup power has not been enabled for this device. */
+	if (!dev->wakeup.prepare_count)
+		goto out;
 
 	err = acpi_device_sleep_wake(dev, 0, 0, 0);
 	if (err)
 		goto out;
 
+	/*
+	 * All of the power resources in the list need to be turned off even if
+	 * there are errors.
+	 */
 	list_for_each_entry(entry, &dev->wakeup.resources, node) {
-		struct acpi_power_resource *resource = entry->resource;
-
-		mutex_lock(&resource->resource_lock);
-
-		if (resource->wakeup_enabled) {
-			err = acpi_power_off_unlocked(resource);
-			if (!err)
-				resource->wakeup_enabled = false;
-		}
-
-		mutex_unlock(&resource->resource_lock);
+		int ret;
 
-		if (err) {
-			dev_err(&dev->dev,
-				"Cannot turn wakeup power resources off\n");
-			dev->wakeup.flags.valid = 0;
-			break;
-		}
+		ret = acpi_power_off(entry->resource);
+		if (ret && !err)
+			err = ret;
+	}
+	if (err) {
+		dev_err(&dev->dev, "Cannot turn off wakeup power resources\n");
+		dev->wakeup.flags.valid = 0;
 	}
 
  out: