On 2016-09-15 09:30, Agustin Benito Bethencourt wrote:
To introduce myself, I'm CEO at Codethink, but to the best of my ability I'll be commenting here from a personal perspective, independent of Codethink's official involvement in CIP.Daniel, can you tell us a little about yourself?I'm now adding another part-time role as lead kernel maintainer for theWelcome to the CIP project. It's great to have such an experienced maintainer
To start the ball rolling, I'm personally worried about how we are actually going to achieve super-long-term-support and am happy that we can discuss the issues in public.
Greg K-H, Ben Hutchings and others have contributed a huge amount to Long Term Stable and followon initiatives in the community over the years. But when I first started exploring how things like LTS and LTSI can work for embedded and automotive in 2012/2013, I hit some fundamental questions, not least - how in practice can a complex embedded project consume a 'stable' kernel that's being released ** every couple of weeks ** with the words 'users of this series must upgrade'? I presented some work at an automotive GENIVI event in Oct 2013  but the audience at that time literally refused to accept that the idea of whole-of-life updates.
And as Greg said at the time:
"The patches that apply for stuff after 2 years drops off dramatically, and the work involved in keeping stuff working and testing for problems increases greatly.”
Just yesterday there was a very interesting post about backports and long term stable kernels on LWN . Greg is quoted there considering:
"But if we didn't provide an LTS, would companies constantly update their kernels to newer releases to keep up with the security and bugfixes? That goes against everything those managers/PMs have ever been used to in the past, yet it's actually the best thing they could do."
I've been recommending the constant update route route to customers over the last few years, with some success, but many ecosystem members are extremely uncomfortable with the whole idea of aligning with mainline. I think this is broadly because as embedded engineers we've learned over many years that it's best to change the platform as little as possible. I wrote an article trying to challenge this traditional embedded thinking earlier this year 
Would be very interested in others' thoughts on this.