On Thu, Apr 14, 2016 at 01:02:56PM +0300, Pantelis Antoniou wrote: > Hi Mark, > > > On Apr 14, 2016, at 12:59 , Mark Rutland <mark.rutland@xxxxxxx> wrote: > > > > On Thu, Apr 14, 2016 at 09:48:49AM +0100, Russell King - ARM Linux wrote: > >> On Thu, Apr 14, 2016 at 04:47:57PM +0900, Masahiro Yamada wrote: > >>> Hi experts. > >>> > >>> My understanding of refcount of DT node is poor. > >> > >> The message from DT people is... don't worry about DT node refcounting. > >> Do whatever you want with it, they don't care whether you have correct > >> refcounting or not. > >> > >> The background behind that is that I've tried to fix the refcounting, > >> and even had the coccinelle people generate some stuff to work on this > >> issue, but DT people's attitude towards it is "don't bother". > >> > >> So yes, people may get it wrong, but it seems it's something that DT > >> people want ignored. > > > > I'm not sure that's quite fair; the last discussion I recall about this > > ended up concluding that we need a better API, rather than papering over > > problems. > > > > That said, there isn't much obvious progress on that front. > > > > Frank, Pantelis, Rob, were there any conclusions on this from ELC, or is > > this something that needs someone to propose something? > > > > Frank mentioned that he wants a new API. I have some ideas about it too. > > My take is that drivers should never do reference counting, we have to figure > out a way for DT access using copy semantics or locks. Generally yes, but I think there may be exceptions. I think the locking is too fine grained for what we need. For almost all users, I think we only need locking at the overlay or changeset level. The only other user I am aware of is PSeries (IIRC) and they only need reference counting for a few things like memory and cpu. I would handle those cases explicitly. But that is going to require someone familar with PSeries to work on. I suppose we could separate overlays from the OF_DYNAMIC dependency (or just the ref counting part of it) and then OF_DYNAMIC goes back to PPC only. Rob -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
