Re: OF_DYNAMIC node lifecycle

On Wed, Jul 16, 2014 at 2:57 PM, Grant Likely [off-list ref] wrote:

On Wed, Jul 16, 2014 at 12:30 PM, Tyrel Datwyler
[off-list ref] wrote:

quoted

On 07/15/2014 10:33 PM, Grant Likely wrote:

quoted

I've got another question about powerpc reconfiguration. I was looking
at the dlpar_configure_connector() function in dlpar.c. I see that the
function has the ability to process multiple nodes with additional
sibling and child nodes. It appears to link them into a detached tree
structure, and the function returns a pointer to the first node.

All of the callers of that function then call dlpar_attach_node(),
which calls of_attach_node(). However, of_attach_node() only handles a
single node. It doesn't handle siblings or children. Is this a bug?
Does the configure connector ever actually receive more than one node
at once?

Yes, it is sometimes the case we will get a tree structure back of more
than one node. Under the proc interface implementation this just worked.
With the move to sysfs it appears we have a regression here. What makes
more sense here, for us to walk the tree calling of_attach_node, or to
move such tree walking logic into of_attach_node? From what I can tell
we are the only consumers of of_attach_node.

That is very shortly going to change. The overlay code also uses
of_attach_node(). I can make of_attach_node() recurse over
descendants, but I'm also considering moving the powerpc code over to
the of_changeset series that Panto and I are working on.

Either way, the handling of multiple nodes should be common code. I
think the easiest is to put the recursion into of_attach_node(), at
least for fixing the bug. It can be reworked later.

On pseries, do notifiers ever fail? ie. Does the reconfig code ever
object to a DT change and prevent it from being applied?

g.