[PATCH v1 1/1] PM: Avoid false-positive warnings in dev_pm_domain_set()

[PATCH v1 1/1] PM: Avoid false-positive warnings in dev_pm_domain_set()

[Andy Shevchenko]

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

There is a WARN_ON() in dev_pm_domain_set() that triggers on attempts
to set the pm_domain pointer for devices with a driver bound.

However, that WARN_ON() triggers on attempts to clear the pointer
too and the test it uses is based on checking the device's
p->knode_driver pointer which still is set when the device bus
type's/driver's ->remove callback has been executed.  This
leads to false-positive warnings when bus type code calls
dev_pm_domain_set() to clear the pm_domain pointer after
invoking the driver's ->remove() callback.

To avoid those false-positives, make dev_pm_domain_set() check
if the pointer passed to it is NULL and skip the warning in
that case.

Fixes: 989561de9b51 (PM / Domains: add setter for dev.pm_domain)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/base/power/common.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/base/power/common.c b/drivers/base/power/common.c
index 93ed14c..f6a9ad5 100644
--- a/drivers/base/power/common.c
+++ b/drivers/base/power/common.c
@@ -146,7 +146,7 @@ void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd)
 	if (dev->pm_domain == pd)
 		return;
 
-	WARN(device_is_bound(dev),
+	WARN(pd && device_is_bound(dev),
 	     "PM domains can only be changed for unbound devices\n");
 	dev->pm_domain = pd;
 	device_pm_check_callbacks(dev);
-- 
2.7.0

Re: [PATCH v1 1/1] PM: Avoid false-positive warnings in dev_pm_domain_set()

[Andy Shevchenko]

On Mon, 2016-02-01 at 16:12 +0200, Andy Shevchenko wrote:
> From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
> 
> There is a WARN_ON() in dev_pm_domain_set() that triggers on attempts
> to set the pm_domain pointer for devices with a driver bound.
> 
> However, that WARN_ON() triggers on attempts to clear the pointer
> too and the test it uses is based on checking the device's
> p->knode_driver pointer which still is set when the device bus
> type's/driver's ->remove callback has been executed.  This
> leads to false-positive warnings when bus type code calls
> dev_pm_domain_set() to clear the pm_domain pointer after
> invoking the driver's ->remove() callback.
> 
> To avoid those false-positives, make dev_pm_domain_set() check
> if the pointer passed to it is NULL and skip the warning in
> that case.
> 
> Fixes: 989561de9b51 (PM / Domains: add setter for dev.pm_domain)
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Oops, it is a wrong one, should be previous.

Btw, this one has been tested and went fine!

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy