Messages in this thread | | | Date | Fri, 17 Apr 2015 13:30:35 -0400 (EDT) | From | Alan Stern <> | Subject | Re: [PATCH v3 1/2] PM / sleep: Let devices force direct_complete |
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On Fri, 17 Apr 2015, Laurent Pinchart wrote:
> Hi Tomeu, > > Thank you for the patch. > > On Friday 17 April 2015 17:24:49 Tomeu Vizoso wrote: > > Introduce a new per-device flag power.force_direct_complete that will > > instruct the PM core to ignore the runtime PM status of its descendants > > when deciding whether to let this device remain in runtime suspend when > > the system goes into a sleep power state. > > > > This is needed because otherwise it would be needed to get dozens of > > drivers to implement the prepare() callback and be runtime PM active > > even if they don't have a 1-to-1 relationship with a piece of HW. > > I'll let PM experts comment on the approach, but I believe the new flag would > benefit from being documented (likely in Documentation/power/devices.txt) :-)
Documentation/power/runtime_pm.txt is the right place.
However, I'm not sure that this is the sort of thing Rafael meant when he suggested adding a new flag. I thought he meant the PM core would look at the new flag only if there was no ->prepare method at all. Then if the new flag was set, the PM core would act as though ->prepare had returned 1. That way there would be no need to add silly little one-line *_prepare() routines all over the place.
Maybe he had something else in mind, though...
Alan Stern
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