| Message ID | 80793506.EZRY3UmSeu@vostro.rjw.lan (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Rafael Wysocki |
| Headers | show |
On Sat, 2016-01-30 at 12:54 +0100, Rafael J. Wysocki 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. Tested on Intel Braswell where modprobe -r sdhci-acpi caused a warning before this patch. Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > > Fixes: 989561de9b51 (PM / Domains: add setter for dev.pm_domain) > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > drivers/base/power/common.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > Index: linux-pm/drivers/base/power/common.c > =================================================================== > --- linux-pm.orig/drivers/base/power/common.c > +++ linux-pm/drivers/base/power/common.c > @@ -146,7 +146,7 @@ void dev_pm_domain_set(struct device *de > 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); >
On 30 January 2016 at 12:54, Rafael J. Wysocki <rjw@rjwysocki.net> 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> > --- > drivers/base/power/common.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > Index: linux-pm/drivers/base/power/common.c > =================================================================== > --- linux-pm.orig/drivers/base/power/common.c > +++ linux-pm/drivers/base/power/common.c > @@ -146,7 +146,7 @@ void dev_pm_domain_set(struct device *de > 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"); Perhaps this information then becomes a bit misleading, as it's okay to clear the pointer, but not assign it to a valid PM domain. > dev->pm_domain = pd; > device_pm_check_callbacks(dev); > Otherwise, this looks good to me! Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Feb 3, 2016 at 10:58 AM, Ulf Hansson <ulf.hansson@linaro.org> wrote: > On 30 January 2016 at 12:54, Rafael J. Wysocki <rjw@rjwysocki.net> 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> >> --- >> drivers/base/power/common.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> Index: linux-pm/drivers/base/power/common.c >> =================================================================== >> --- linux-pm.orig/drivers/base/power/common.c >> +++ linux-pm/drivers/base/power/common.c >> @@ -146,7 +146,7 @@ void dev_pm_domain_set(struct device *de >> 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"); > > Perhaps this information then becomes a bit misleading, as it's okay > to clear the pointer, but not assign it to a valid PM domain. Well, this is a "you're doing a wrong thing" warning and it does say what the wrong thing is. Does it have to be more specific? I don't think so. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 3 February 2016 at 13:08, Rafael J. Wysocki <rafael@kernel.org> wrote: > On Wed, Feb 3, 2016 at 10:58 AM, Ulf Hansson <ulf.hansson@linaro.org> wrote: >> On 30 January 2016 at 12:54, Rafael J. Wysocki <rjw@rjwysocki.net> 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> >>> --- >>> drivers/base/power/common.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> Index: linux-pm/drivers/base/power/common.c >>> =================================================================== >>> --- linux-pm.orig/drivers/base/power/common.c >>> +++ linux-pm/drivers/base/power/common.c >>> @@ -146,7 +146,7 @@ void dev_pm_domain_set(struct device *de >>> 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"); >> >> Perhaps this information then becomes a bit misleading, as it's okay >> to clear the pointer, but not assign it to a valid PM domain. > > Well, this is a "you're doing a wrong thing" warning and it does say > what the wrong thing is. Does it have to be more specific? I don't > think so. Okay! I don't have a strong opinion. Feel free to add: Acked-by: Ulf Hansson <ulf.hansson@linaro.org> Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Index: linux-pm/drivers/base/power/common.c =================================================================== --- linux-pm.orig/drivers/base/power/common.c +++ linux-pm/drivers/base/power/common.c @@ -146,7 +146,7 @@ void dev_pm_domain_set(struct device *de 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);