Jason, On Mon, 6 Apr 2015 14:46:47 +0000, Jason Cooper wrote: > This causes two problems: > > 1) Upgrade kernel, but not DTB. > > System will boot, and print a big fat warning that > suspend/resume will not work until the DTB is upgraded. > > 2) Upgrade DTB, but not kernel. > > System will fail to boot. (2) has never been something that has ever planned of being guaranteed, as far as I know. Only (1) is the supposed consequence of DT ABI stability, but definitely not (2), so I'm unsure why you even mention (2). > In light of Thomas Petazonni's well-researched talk at ELC: > > "The Device Tree as a stable ABI: a fairy tale?" > http://events.linuxfoundation.org/sites/events/files/slides/petazzoni-dt-as-stable-abi-fairy-tale.pdf > > I'm confident that #2 won't be an issue. Distro's and OEMs seem to have > worked around the instability by keeping the dtb tied to the kernel > version. I'm glad you raised my slides as an argument in a DT ABI stability discussion :-) However, my slides are definitely not about #2 (which as said earlier, was never planned to be something we should worry about), but really about #1. But the point of the slides stand: even for a piece of hardware as well-documented as the GIC, as widely used as the GIC, with as many bright and smart engineers looking into it, the community has not been able to put out a DT binding that can be kept stable. How can we expect such a DT binding stability to occur for undocumented hardware, or SoC-specific hardware blocks that are definitely a lot less used than the GIC ? Best regards, Thomas Petazzoni -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- 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
