On Thu, Jun 13, 2013 at 11:56 AM, Paul Fox <p...@laptop.org> wrote: > does this imply a future flag day, at which time new firmware will be > incompatible with old kernels, and vice-versa?
Unfortunately even without the DT changes described here, old firmware versions already will not be able to boot new/upstream kernels, once we get to that point. The DT is missing regulator information so the MMC controller doesn't get powered up. This is the "old firmware, new kernel" problem. The DT clock changes described here would also mean that new firmwares become incompatible with released kernels. This is the "new firmware, old kernel" problem. I think this will also be unavoidable. So yes, we are looking at both of those problems. There are some thoughts and possibilities here: http://wiki.laptop.org/go/Device_tree_upgrade_considerations https://lists.ozlabs.org/pipermail/devicetree-discuss/2012-August/019024.html but no definite, attractive solution. I suspect it is something we are just going to have to live with. I think the "old firmware, new kernel" is the most painful of the two problems. Maybe we can fix that up with a bootwrapper type solution mentioned in the mail linked to above (and maybe I already half-wrote the bootwrapper in my previous mail). There is also the possibility that the kernel will accept bindings for old/imperfect DTs once good bindings are put in place - or alternatively we could patch them in. I'm working on the "good bindings" aspect at the moment. Daniel _______________________________________________ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
