mismatch between default and defconfig LOG_BUF_SHIFT values

mismatch between default and defconfig LOG_BUF_SHIFT values

[Robert P. J. Day]

  not like it's a big deal, but there's a minor incongruity between
the default values for LOG_BUF_SHIFT for IA64 depending on whether
you're configuring for the first time or not.

  if i'm configuring with a fresh tree for the first time (so that
there's no .config file) and i run:

  $ make ARCH=ia64 menuconfig    (on my x86 system, just for fun)

then the initial value for LOG_BUF_SHIFT is obtained from
arch/ia64/defconfig:

  CONFIG_LOG_BUF_SHIFT=20

however, once i do that initial config, if i deselect "Kernel
debugging" and later reselect it, the new default value of 16 for that
config option comes from lib/Kconfig.debug:

...
config LOG_BUF_SHIFT
        int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
        range 12 21
        default 17 if S390 || LOCKDEP
        default 16 if X86_NUMAQ || IA64     <-- 16, not 20
...

  is it worth trying to bring the Kconfig.debug default values into
line with the defconfig file values, to avoid any possible confusion?

rday

Re: mismatch between default and defconfig LOG_BUF_SHIFT values

[Arjan van de Ven]

> ...
> 
>   is it worth trying to bring the Kconfig.debug default values into
> line with the defconfig file values, to avoid any possible confusion?

I don't think so. 
defconfig is just there to get some working system. You should really
pay attention to the config options you care about, and select the value
YOU want. Neither defconfig nor the "default value" matter in that.
Of course especially the "default value" should be a sane one, but it is
in this case.. your system boots and works fine.

defconfig also tends to be the config used by the arch maintainer, eg
the one he uses for his system. He might very well have different
preferences than you have...


-- 
if you want to mail me at work (you don't), use arjan (at) linux.intel.com
Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org

Re: mismatch between default and defconfig LOG_BUF_SHIFT values

[Robert P. J. Day]

On Tue, 28 Nov 2006, Arjan van de Ven wrote:

> > ...
> >
> >   is it worth trying to bring the Kconfig.debug default values into
> > line with the defconfig file values, to avoid any possible confusion?
>
> I don't think so. defconfig is just there to get some working
> system. You should really pay attention to the config options you
> care about, and select the value YOU want. Neither defconfig nor the
> "default value" matter in that. Of course especially the "default
> value" should be a sane one, but it is in this case.. your system
> boots and works fine.
>
> defconfig also tends to be the config used by the arch maintainer,
> eg the one he uses for his system. He might very well have different
> preferences than you have...

fair enough.  i didn't *think* there was any technical reason why
those values had to match, i just thought i'd ask.

rday