On 8 December 2013 21:50, Mark Brown broonie@kernel.org wrote:
On Sun, Dec 08, 2013 at 07:51:59PM +0000, Peter Maydell wrote:
On 8 December 2013 19:22, Mark Brown broonie@kernel.org wrote:
(and doesn't reflect the actual deployed code reading the binding which does use this property without documentation outside ePAPR and does warn if it's absent)
This code should be fixed, then... (I'm pretty sure the kernel has not always warned about the absence of this property, or there would not be such a wide prevalence of DTs and DT generating code which omitted it.)
Too late for that, it's shipping in stable kernels.
There does come a point where it's just nitpicking and not helpful but if it has a substantial effect on functionality then it's useful. In this case suppressing the warning for non-asymmetric systems might be sensible.
Hmm, so "mandatory for non-symmetric [I assume you mean that and not really 'non-asymmetric'?], otherwise optional" ? I think that would be reasonable and preserve backwards compatibility.
For all practical purposes it is currently optional but the spec says it is mandatory. I would rather err on the side of not changing the documentation in case someone does work based on ePAPR and/or an old kernel and since doing that keeps the spec more stable even if we do implement in a more tolerant fashion within Linux (as we should).
As I say, I don't think your specification currently does say it is mandatory. If the documentation doesn't clearly list it as a mandatory parameter, and a large number of people writing DTS files or DT generation code haven't put it in, and the kernel didn't complain about it not being present for a long long time, then de facto it is optional, and you should make your documentation conform with reality and fix bugs where the kernel isn't coping with that.
thanks -- PMM