Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH] PM / runtime: Fix handling of suppliers with disabled runtime PM | Date | Fri, 01 Dec 2017 15:29:44 +0100 |
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On Friday, December 1, 2017 3:18:01 PM CET Lukas Wunner wrote: > On Fri, Dec 01, 2017 at 02:58:34PM +0100, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > > > Prevent rpm_get_suppliers() from returning an error code if runtime > > PM is disabled for one or more of the supplier devices it wants to > > runtime-resume, so as to make runtime PM work for devices with links > > to suppliers that don't use runtime PM (such links may be created > > during device enumeration even before it is known whether or not > > runtime PM will be enabled for the devices in question, for example). > > > > Reported-by: Adrian Hunter <adrian.hunter@intel.com> > > Fixes: 21d5c57b3726 (PM / runtime: Use device links) > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > --- > > drivers/base/power/runtime.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > Index: linux-pm/drivers/base/power/runtime.c > > =================================================================== > > --- linux-pm.orig/drivers/base/power/runtime.c > > +++ linux-pm/drivers/base/power/runtime.c > > @@ -276,7 +276,8 @@ static int rpm_get_suppliers(struct devi > > continue; > > > > retval = pm_runtime_get_sync(link->supplier); > > - if (retval < 0) { > > + /* Ignore suppliers with disabled runtime PM. */ > > + if (retval < 0 && retval != -EACCES) { > > pm_runtime_put_noidle(link->supplier); > > return retval; > > } > > > > You could alternatively call pm_runtime_get_sync() under the condition > link->supplier->power.disable_depth > 0 but then the usage_count wouldn't > be incremented and I guess we want that in case runtime PM is only > temporarily disabled and later enabled, right? > > I'm wondering if checking for that condition in lieu of retval != -EACCES > would be more explicit and less fragile here (there's a theoretical > possibility that the supplier's ->runtime_resume callback returns -EACCESS, > leading to a false positive).
That will be filtered out by rpm_callback() which converts -EACCES to -EIO.
> > Apart from that, > > Reviewed-by: Lukas Wunner <lukas@wunner.de>
Thanks, Rafael
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