Ubuntu ARM and the linaro kernels

[Manoj Iyer]

ogra,

Did you see the mail to kernel mailing list where someone wanted to
add DVB drivers ( http://www.tevii.com) to our tree?, Realtek is
another example. The issue with such drivers can be that they are not
upstream or in beta, but are unsupported. Unless we have a commitment
from the driver developers that they are willing to support these
drivers I don't think we can add them to our tree safely.  Not sure if
you guys have thought about such a situation.

-- 
manjo

 PM, Oliver Grawert <ogra at ubuntu.com> wrote:
> hi,
> Am Montag, den 15.11.2010, 08:53 -0700 schrieb John Rigby:
>> On Mon, Nov 15, 2010 at 4:28 AM, Loïc Minier <loic.minier at ubuntu.com> wrote:
>> >  Folks, I think this thread is circling a bit back to itself, perhaps
>> >  summarizing where we stand and what problems we're trying to solve
>> >  would help?
>> >
>> >
>> >  * Linaro integrates its kernel tree into Ubuntu for two reasons:
>> >   - because Linaro uses Ubuntu as a base to build its own derived
>> >     images (out of Ubuntu)
>> >   - because Linaro wants its kernel shipped/available in distributions
>> >     such as Ubuntu/MeeGo/whatever for mutual benefit of the distro and
>> >     of Linaro.  For instance, Ubuntu users could install this kernel
>> >     instead of the official Ubuntu one, or Ubuntu could build images
>> >     from this kernel (as proposed in the original email).
>> >
>> >  * there are currently the following *three* trees for the Ubuntu Linaro
>> >   kernel packages to happen (for maverick):
>> >   - git://git.linaro.org/kernel/linux-linaro-2.6.35.git -- upstreamish
>> >     tree maintained by Nicolas, based on upstream git tree with patches
>> >     relevant to Linaro merged in; the Linaro Kernel
>> >   - git://git.linaro.org/ubuntu/linux-linaro.git -- Ubuntu-ish tree
>> >     for the linux-linaro source package in Ubuntu or in Linaro PPAs
>> >     maintained by jcrigby, based on the Linaro Kernel tree with
>> >     packaging and the Ubuntu stuff ("Sauce") merged in
>> >   - git://kernel.ubuntu.com/ubuntu/ubuntu-maverick.git linaro branch --
>> >     pretty much the same as jcrigby's tree maintained by the Ubuntu
>> >     kernel team; it's mostly a copy of jcrigby's tree when it gets
>> >     uploaded to Ubuntu, unless the Ubuntu kernel team has to do any
>> >     minor adjustments/fixups before upload; it exists only because
>> >     jcrigby can't upload and because /ubuntu is restricted to the
>> >     official Ubuntu Kernel Team
>> >
>> >  So what problems / questions are we trying to solve?
>> >  * security support: Linaro isn't in the business of long-term security
>> >   support of its trees, however I understand that it wouldn't be a big
>> >   problem to simply add the *Ubuntu* linux-linaro package and the
>> >   kernel.ubuntu.com git tree to the list of packages/trees which get
>> >   security updates from the Ubuntu Security Team, especially if the
>> >   Ubuntu ARM Team moves to this package/tree as their base for some
>> >   images
>> >  * for Linaro, the Ubuntu Sauce stuff doesn't add any much value and is
>> >   a distraction (causes more merge efforts, might cause extra bugs
>> >   etc.)
>> >
>> >
>> >  Is this a fair summary?  Did I miss anything?
>> >
>> >
>> >  I am not sure I understand the point of contention with the Ubuntu
>> >  Sauce stuff; is it causing problems to Linaro right now?
>> >   Linaro GCC is released in source form and then integrated in the
>> >  Ubuntu gcc-4.x packages which have tons of patches added on top; this
>> >  is not ideal for Linaro Toolchain WG, but it's part of the process to
>> >  check whether bugs do apply to the pristine Linaro source, just like
>> >  you need to test a pristine upstream GCC or Linux when reporting bugs
>> >  upstream.
>> >
>> >  There are definitely things we could do to improve the Ubuntu Sauce:
>> >  * split this stuff more; e.g.:
>> >   - packaging goes in one tree (I think this is already split out?)
>> >   - patches which come from upstream or were acked upstream go into
>> >     another tree
>> >   - patches which are Ubuntu specific such as AUFS go into one or
>> >     multiple separate trees
>> >  * we could review the current sauce stuff and only merge in features
>> >   which are really needed for Linaro images and Ubuntu ARM images; aufs
>> >   doesn't seem to be needed anymore for instance?  Maybe this makes
>> >   things more complex for little gain though
>> >  * we could stop merging patches from upstream from Ubuntu, and have
>> >   them flow in via Linaro instead; again, maybe this makes things more
>> >   complex for little gain
>> >
>> >
>> >  My opinion is that the current approach is okay modulo two things:
>> >  - we should drop one of the two packaging trees; the
>> >   linaro / jcrigby versus kernel.ubuntu.com split is useless
>> >  - we could provide pristine kernel builds, built from the Linaro Kernel
>> >   directly and without any Ubuntu Sauce
>> >   . in fact these exist already, they just aren't tested and they use a
>> >     random config: http://hudson.dooz.org/
>> >   . if we want Linaro Kernel .debs instead of standalone zImage/uImage,
>> >     we could do something like
>> >     https://wiki.ubuntu.com/Kernel/MainlineBuilds
>> >
>> >
>> >  Proposed plan
>> >  * Oliver/Ricardo to confirm with Ubuntu Security Team whether it's ok
>> >   to base Ubuntu ARM images on linux-linaro tree as constructed
>> >   currently
>> I can't speak for the Ubuntu ARM folks but I believe their main concern was if
>> I stopped including Ubuntu Sauce.
> right, that was one of my concerns, another was how much the kernels
> differ from BSP source we usually use for ubuntu images so that all
> on-board devices work out of the box.
>
> then there is the question about ubuntu configs (which you answered)
> (since we try to keep our QA efforts low we expect the same or a close
> to same config to the ubuntu kernel in the arm kernels (i.e. a user
> needs to be able to plug in his DVB-T USB stick and get the same results
> in ubuntu arm as he gets on his ubuntu laptop))
>
> my main concern though is the 18 month support timeframe which we
> provide for ubuntu images.
>
> i think from the linaro side i got sufficient answers now, it seems we
> could use johns trees as a base for ubuntu images but would have to have
> someone from the ubuntu kernel team and the ubuntu security team for
> maintaining security and config alignment.
>
> the situation in the kernel team wrt arm maintenance is just being
> sorted afaik, so i expect to get some info in this thread in the not to
> far future ...
>
> ciao
>        oli
>
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-- 
Cogito Ergo Sum
--- manjo