Re: [PATCH v4 19/21] drivers/of: Support adding sub-tree

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




On Sat, 2015-05-02 at 08:57 +1000, Benjamin Herrenschmidt wrote:

> > Overlay = an FDT blob to graft into a live running system. Sounds like
> > the same thing.
> > 
> > > As for the details of Gavin implementation, I haven't looked at it in
> > > details yet so there might be issues there, however I don't know what
> > > you mean by "overlays", any pointer ?
> > 
> > CONFIG_OF_OVERLAY
> > 
> > http://events.linuxfoundation.org/sites/events/files/slides/dynamic-dt-keynote-v3.pdf
> 
> Well, that looks horrendously complicated, poorly documented and totally
> unused in-tree outside of the unittest stuff, yay ! It has all sort of
> "features" that I don't really care about.

Looking a bit more at it, I don't quite see how I can attach a subtree
using that stuff.

Instead, each node in the overlay seems to need extra nodes and
properties to refer to the original.

So the FW would essentially have to create something a lot more complex
than just reflattening a bit of its internal tree. For each internal
node, it will need to add all those __overlay__ nodes and properties.

That is not going to fly for me at all. It's order of magnitudes more
complex than the solution we are pursuing.

So I think for our use case, we should continue in the direction of
having a helper to unflatten a piece of FDT underneath an existing
node. I don't like the "HYBRID" stuff though, we should not refer to
the original FDT, we should just make them normal dynamic nodes.

Ben.



--
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




[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]
  Powered by Linux