Messages in this thread | | | Date | Mon, 10 Oct 2011 11:48:11 +0300 | From | Adrian Bunk <> | Subject | Re: Please revert "debug: Make CONFIG_EXPERT select CONFIG_DEBUG_KERNEL to unhide debug options" |
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On Mon, Oct 10, 2011 at 09:29:48AM +0200, Ingo Molnar wrote: > * Adrian Bunk <bunk@stusta.de> wrote: >... > I think you are wrong not just about that detail but about the whole > premise of your complaint as well: > > > config DEBUG_BUGVERBOSE > > - bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT > > + bool "Verbose BUG() reporting (adds 70K)" if EXPERT > > > > This part of the patch would have been the correct and complete > > solution for DEBUG_BUGVERBOSE. > > Not really - it's a debugging-only option and when i turn on > CONFIG_DEBUG_KERNEL I expect to have full config control over all > debug options - with sane defaults provided.
Then you would have to remove the dependency on EXPERT from the prompt, and allow unsetting DEBUG_BUGVERBOSE with EXPERT=n, DEBUG_KERNEL=y.
Note that this is completely unrelated to the commit we are discussing, since commit f505c553 has no effect in the EXPERT=n case you are discussing here.
> I definitely don't want a debugging option to depend on > CONFIG_EXPERT.
DEBUG_BUGVERBOSE does not depend on EXPERT.
But EXPERT is currently required for disabling it.
This part of our discussion boils down to the following options: 1. DEBUG_KERNEL allows a user to enable additional debugging 2. DEBUG_KERNEL gives a user full control over all debug options
Traditionally it was 1., to tell a user reporting a bug that he should enable additional debugging in his kernel - without him accidentally disabling useful debugging.
Again, this part of the discussion is unrelated to commit f505c553.
> CONFIG_EXPERT is a superset to all that: it implies config control > over all debug options *and* over many other kernel components as > well.
I don't see the advantage that EXPERT=y is now unconditionally enabling the DEBUG_KERNEL knob.
When I am an "expert", why can't I still decide myself globally if I want to enable more debugging or not?
Another problem is that we have code using "#ifdef CONFIG_DEBUG_KERNEL" so enabling EXPERT for making your kernel smaller can make your kernel bigger, but such usages should anyway get own config options.
> This is a pretty easy model to think about.
There are many options in the kernel that only enable seeing other config options.
With that model, shouldn't EXPERT also have select MISC_FILESYSTEMS and many other similar select's?
The point I am trying to make here is that there are many convenience config options that only exist to allow a user to hide a bunch of options he is not interested in, and DEBUG_KERNEL is one of them. [1]
> > The crazy select added in commit f505c553 is wrong. > > Why? Your original message does not explain it.
It is not needed for what it was claimed it was needed for, and it is a bad idea in general.
If I didn't explain that properly that was my fault, I hope the explanation in this email is better.
> Thanks, > > Ingo
cu Adrian
[1] ignoring the buggy code using "#ifdef CONFIG_DEBUG_KERNEL"
--
"Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed
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