Re: [Ksummit-discuss] [MAINTAINERS SUMMIT] Pull network and Patch Acceptance Consistency

[Mauro Carvalho Chehab <mchehab+samsung@kernel.org>]

Em Fri, 14 Jun 2019 08:23:05 -0700
James Bottomley <James.Bottomley@HansenPartnership.com> escreveu:

> On Fri, 2019-06-14 at 12:11 -0300, Mauro Carvalho Chehab wrote:
> [...]
> > If you think this is relevant to a broader audience, let me reply
> > with a long answer about that. I prepared it and intended to reply to
> > our internal media maintainer's ML (added as c/c). 
> > 
> > Yet, I still think that this is media maintainer's dirty laundry
> > and should be discussed elsewhere ;-)
> > 
> > ---  
> 
> So trying not to get into huge email thread, I think this is the key
> point:
> 
> [...]
> > Currently, I review all accepted patches.  
> 
> This means you effectively have a fully flat tree.

Yes.

> Even if you use
> git, you're using it like an email transmission path.  One of the
> points I was making about deepening the tree is that the maintainer in
> the middle should trust the submaintainer they pull from, so there
> should be no need to review all the patches because of that trust. 

It is not a matter of trust. It is just that the media subsystem is
a complex puzzle. Just the V4L2 API has more than 80 ioctls.

So, the goal here is to do my best to ensure that patches will get
at least two reviews.

> This is how deepening the tree helps to offload maintainers because
> review is one of the biggest burdens we have and deepening the tree is
> a way to share it.  Without trust, we achieve no offloading and
> therefore no utility from deepening the tree.

Yeah, I know one day this won't scale. The day it happens, I'll
just start picking pull requests. As we already use git, a change 
like that would be trivial.

> So, to get back to the original question, which was *should* we deepen
> the tree: why don't you feel you can let branches with patches you
> haven't reviewed into your tree?  I've characterised it as a trust
> issue above, but perhaps it isn't. I think this is a key question which
> would help us understand whether a deeper tree model is at all
> possible.

One of the aspects is that developers nowadays are specialists on a
subset of the media devices. Most of them are working on complex 
camera support, with envolves a subset of the APIs we have. They
never worked on a driver that would use other parts of the API, like
DVB, Remote Controllers, TV, V4L2 streaming devices, etc.

So, having someone with a more generalist view at the end of the
review process helps to identify potential problems that might
affect other devices, specially when there are API changes involved[1].

[1] Since when I started maintaining the subsystem, back on 2005,
on almost every single Kernel review there are API changes in
order to support new types of hardware.

Thanks,
Mauro