On 12/05/2013 06:01 PM, Ian Campbell wrote: > On Thu, 2013-12-05 at 13:39 +0100, Marc Kleine-Budde wrote: >> On 12/05/2013 01:15 PM, Ian Campbell wrote: >>> On Thu, 2013-12-05 at 13:04 +0100, Marc Kleine-Budde wrote: >>>> On 12/05/2013 12:57 PM, Ian Campbell wrote: >>>>> On Thu, 2013-12-05 at 12:46 +0100, Marc Kleine-Budde wrote: >>>>>> On 12/05/2013 12:34 PM, Martin Michlmayr wrote: >>>>>>> * Marc Kleine-Budde <mkl@blackshift.org> [2013-12-05 11:49]: >>>>>>>> That's no option, as non DT Sheeva Plug support has been removed from >>>>>>>> the kernel in ffbc50663b69462adc9d97b93b6b92c4fe74b94c: >>>>>>>> >>>>>>>> ffbc506 ARM: kirkwood: remove support for legacy booting of Sheevaplug >>>>>>> >>>>>>> Interesting. I thought they promised not to remove non-DT support for >>>>>>> existing devices. >>>>>> >>>>>> I personally don't mind, if it's removed once the DT works properly. >>>>>> >>>>>>> Anyway, Marc, so thanks for your patch. I wonder if it makes sense to >>>>>>> add a check to flash-kernel whether DT is required or not. i.e. that >>>>>>> flash-kernel would append the DT blob on 3.12+ kernels on SheevaPlug >>>>>>> but not on previous kernels. >>>>>> >>>>>> Yes, sounds like the way to go. Otherwise you have to tie certain >>>>>> flash-kernel versions to the non-DT and DT kernels. This will probably >>>>>> not scale when more no-DT board are removed from the kernel. >>>>>> >>>>>> Where should this information go? What about adding another field to >>>>>> all.db which limits an entry to certain kernel versions? Something like >>>>>> this: >>>>> >>>>> I think it would be sufficient to have a field marking the DTB as >>>>> optional and have f-k only do the append if there is a dtb present in >>>>> the DTS directory (/usr/lib/linux-X.Y/whatever) for the version it is >>>>> handling. If the kernel needs a DTB but doesn't ship one, well ,that's a >>>>> bug in the kernel (until we get to the point of burning DTBs into >>>>> firmware, but lets not worry about that now!). >>>> >>>> ...or when the DT sources will be move into a separate repository. >>> >>> Indeed. >>> >>> Actually, now that I think about it -- a non-DT aware kernel just >>> shouldn't care if you append a DT to it, it won't ever go looking. It's >>> probably safe to just append it unconditionally. >> >> Yes, should be safe. >> >>> Which is what you did, so we've come full circle, sorry for the >>> distraction. >> >> It's good to talk about the implications. If we want to handle >> downgrading of kernels with an updated flash-kernel, I think, that >> cannot be done without an additional Kernel-Version field. >> >> This is because v3.11 ships with: >> >> /usr/lib/linux-image-3.11-2-kirkwood/kirkwood-sheevaplug.dtb >> >> But non-DT Sheeva support is still in the kernel, so non-DT Sheeva Plug >> is used with current flash-kernel and v3.11. Although v3.10 and v3.11 >> are not Wheezy's kernels. > > Is 3.11+DTB actively broken though? v3.11+DT works on Sheeva Plug, just tested it. I was thinking of the following scenario: I have installed current flash-kernel (without DT support) and kernel v3.11. Then the new flash-kernel with append-DT-if-present-in-the-Kernel-package feature is released together with a new DT only kernel (=v3.12). I upgrade, because I want to have the shiny new kernel. For whatever reason I want to downgrade to v3.11, then I end up with v3.11 with DT, because the flash-kernel is still the new one. The system does not behave as I expected. I downgraded to the same kernel but now the DT Sheeva Plug is booted. Although the bootloader sets the ARCH number, a attached DT seems to be preferred. >>> I suppose it would be nice to just check that the Wheezy kernel doesn't >>> complain about or get confused by the appended DTB. Can you check that? >> >> I don't have physical access to that Sheeva Plug. > > Hrm, this would be something which would be good to try somewhere. On Wheezy there is no Sheevaplug DTB to attach... > Now I think of it the Wheezy kirkwood kernel did have DT and > APPENDED_DTB support enabled, in order to support dreamplugs. http://packages.debian.org/wheezy/armel/linux-image-3.2.0-4-kirkwood/filelist Wheezy has two dtb files: /usr/lib/linux-image-3.2.0-4-kirkwood/kirkwood-dreamplug.dtb /usr/lib/linux-image-3.2.0-4-kirkwood/kirkwood-iconnect.dtb > I have a feeling that would mean that it wouldn't boot if you appended a > dtb to it. Which would mean we do have to think about versioned checks > or something. Just stating the obvious: The Sheeva Plug probably wouldn't boot if I attach a dreamplug dtb to it. :) Marc
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