Re: [RFC] Simplifying kernel configuration for distro issues

On Fri, 2012-07-13 at 13:37 -0700, Linus Torvalds wrote:
> So this has long been one of my pet configuration peeves: as a user I
> am perfectly happy answering the questions about what kinds of
> hardware I want the kernel to support (I kind of know that), but many
> of the "support infrastructure" questions are very opaque, and I have
> no idea which of the them any particular distribution actually depends
> on.
[...]
> The point I'm slowly getting to is that I would actually love to have
> *distro* Kconfig-files, where the distribution would be able to say
> "These are the minimums I *require* to work". So we'd have a "Distro"
> submenu, where you could pick the distro(s) you use, and then pick
> which release, and we'd have something like

I like this idea in principle.

[...]
>  - distro/Kconfig:
> 
>     config DISTRO_REQUIREMENTS
>         bool "Pick minimal distribution requirements"
> 
>     choice DISTRO
>         prompt "Distribution"
>         depends on DISTRO_REQUIREMENTS
> 
>     config FEDORA
>     config OPENSUSE
>     config UBUNTU
>     ...
> 
>     endchoice
> 
> and then depending on the DISTRO config, we'd include one of the
> distro-specific ones with lists of supported distro versions and then
> the random config settings for that version:

You might also want to *un*select some options like
CONFIG_SYSFS_DEPRECATED and CONFIG_SYSFS_DEPRECATED_V2 that need to be
set one way or the other depending on the version of udev.  (I think
it's possible to kluge this with the addition of a hidden negative
config option.)

How about stuff like NET and INET, that every distro will need and yet
is configurable even without EXPERT?

[...]
> Sure, you can copy the config file that came with the distro, but it
> has tons of stuff that really isn't required. Not just in hardware,
> but all the debug choices etc that are really a user choice. And it's
> really hard to figure out - even for somebody like me - what a minimal
> usable kernel is.
[...]

And it's still hard for me as kernel packager: just because an option
was requested and enabled to support some bit of userland, doesn't mean
I know what's using or depending on it now.  (I think Dave Jones made
this point already.)  I'm not usually concerned with *minimal* config.

Ben.

-- 
Ben Hutchings
The generation of random numbers is too important to be left to chance.
                                                            - Robert Coveyou