Re: [gentoo-user] gentoo-sources menuconfig feature/weirdness

On Fri, Feb 24, 2012 at 11:02:38PM +0000, Neil Bothwick wrote:
> On Fri, 24 Feb 2012 14:11:24 -0800, ny6p01@×××××.com wrote:
>
> > Or just import .config into the 'New' directory, and run plain ol' make
> > menuconfig. Menuconfig will import what it can from the old config. From
> > what I've read of the docs, make oldconfig is the dangerous part that
> > should be avoided between substantial kernel updates.
>
> make oldconfig is not the risk, importing the old config is. oldconfig
> tries to convert the old config to suit the new kernel, with a success
> rate probably in excess of 99%, despite what has been written about it.
>
> Using the old .config without make oldconfig is a good way of getting
> the worst of both worlds.
>
>
> --
> Neil Bothwick
>
> Windows Error #56: Operator fell asleep while waiting.


I don't mean to be petty, so forgive me - but I needed to check to see if
I'd misread the kernel upgrade guide. So I went back and checked the guide,
and I was confirmed in my impression. From the guide:

#Start Quotes
It is sometimes possible to save time by re-using the configuration file
from your old kernel when configuring the new one. Note that this is
generally unsafe -- too many changes between every kernel release for this
to be a reliable upgrade path.

The only situation where this is appropriate is when upgrading from one
Gentoo kernel revision to another. For example, the changes made between
gentoo-sources-2.6.9-r1 and gentoo-sources-2.6.9-r2 will be very small, so
it is usually OK to use the following method. However, it is not appropriate
to use it in the example used throughout this document: upgrading from 2.6.8
to 2.6.9. Too many changes between the official releases, and the method
described below does not display enough context to the user, often resulting
in the user running into problems because they disabled options that they
really didn't want to.

To reuse your old .config, you simply need to copy it over and then run make
oldconfig. In the following example, we take the configuration from
gentoo-sources-2.6.9-r1 and import it into gentoo-sources-2.6.9-r2. 

A much safer upgrading method is to copy your config as previously shown,
and then simply run make menuconfig. This avoids the problems of make
oldconfig mentioned previously, as make menuconfig will load up your
previous configuration as much as possible into the menu. Now all you have
to do is go through each option and look for new sections, removals, and so
on. By using menuconfig, you gain context for all the new changes, and can
easily view the new choices and review help screens much easier. You can
even use this for upgrades such as 2.6.8 to 2.6.9; just make sure you read
through the options carefully. Once you've finished, compile and install
your kernel as normal.

#End Quotes


Terry