On Thu, Jan 04, 2018 at 03:08:08PM -0700, Ian Lepore wrote: > On Thu, 2018-01-04 at 15:47 -0600, Kyle Evans wrote: > > On Thu, Jan 4, 2018 at 3:34 PM, Kyle Evans <kevans@xxxxxxxxxxx> wrote: > > > > > > On Thu, Jan 4, 2018 at 2:41 PM, Kyle Evans <kevans@xxxxxxxxxxx> wrote: > > > > > > > > On Thu, Jan 4, 2018 at 2:33 PM, Frank Rowand wrote: > > > > > > > > > > [... snip ...] > > > > > > > > > > Does this remove the need for the proposed patch, or am I still > > > > > missing something? > > > > ... nope. Apparently I never tested this with this particular dtc(1) > > > > and instead just assumed it did the same as ours- allocate phandle > > > > sparsely, even with -@. That certainly removes the need for this > > > > patch, and I'm somewhat upset that I hadn't previously considered > > > > this. > > > > > > > > @David, Jon: Please disregard all of the patches along these lines... > > > > I'll fix this in our dtc, where it should be fixed. > > > > > > > > Thanks, Frank! > > > Actually, I'm kind of torn on whether this is useful or not. With > > > being able to have EFI-provided FDT, it's hard to guarantee whether > > > the FDT we're provided has been compiled with GPL dtc(1) and -@. The > > > above solves this problem for most of my personal use-cases , though, > > > since I can guarantee that our FDT and U-Boot provided FDT is compiled > > > properly. > > Apologies for the triple post; I realized that this argument is > > inherently wrong, since we can't reference the node if there's no > > symbol anyways. > > > > The only way this might still be a good idea is to support more > > minimal cases where an implementation might prefer to not create a > > phandle for nodes that haven't been referenced. > > > > In our case, we have a function [1] that walks the tree and generates > > metadata on nodes that have phandles, under the assumption that these > > have been referenced somewhere and provides a way to more quickly > > reference these specifically through a separate linked link. > > Allocating phandles for everything as GPL dtc does adds quite a bit > > more overhead to this. > > > > [1] http://src.illumos.org/source/xref/freebsd-head/sys/dev/ofw/openfirm.c#119 > > In particular, it makes lookups more expensive as it now must traverse > a list that includes every node in the dtb, rather than just nodes that > are actually referenced. (It also increases the amount of storage, but > at 20-ish bytes per node, that's not a big deal.) Lookups of what exactly? Aren't you unflattening the tree after you read it in? -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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