Messages in this thread | | | Date | Wed, 9 Jan 2013 13:00:04 +0000 | From | Lee Jones <> | Subject | Re: [PATCH 2/3] ARM: ux500: Turn on the 'heartbeat' LED trigger |
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> > Excuse my ignorance, but I'm a little confused by this. > > > > What's the difference between 'select <OPTION>' in the Kconfig and > > 'CONFIG_<OPTION>=y' in the defconfig; besides the fact that if we > > do it in the Kconfig file, we can be more selective with regards to > > which platform it gets enabled on? > > Take this in Kconfig: > > config FOO > bool "FOO option" > select BAR > > config BAR > bool "BAR option" > > Now, irrespective of the default configuration file being used: > - if you don't enable FOO, then you can enable _and_ _disable_ BAR according > to your needs. > - if you enable FOO, then BAR will be _forcefully_ enabled and you can't > turn it off without first disabling FOO. > > The default configuration file will specify the _default_ values for these > options, but if FOO ends up being enabled, BAR will be forcefully enabled > irrespective of what's in the configuration file. > > With this instead: > > config FOO > bool "FOO option" > > config BAR > bool "BAR option" > > Then, the two options are independent. They can be enabled and disabled > by the configuration completely independently. However, their default > values come from the default configuration file. So, if the config file > has: > > CONFIG_FOO=y > CONFIG_BAR=y > > and you do a 'make oldconfig' then they will remain set. If you use one > of the configuration editing tools, you'll be presented with them already > enabled, and you can turn them off independently. > > So, putting this stuff in the default configuration file allows > _non-mandatory_ options to be disabled should the user desire without the > user having to edit the configuration files. > > If a user has to edit the configuration files in order to configure the > kernel as they desire, then the configuration system has failed - or we > have failed to properly think out how to represent the allowable > configurations.
Understood. Thanks for the explanation.
Linus, is it okay to put these in the defconfig instead?
If so, I'll fixup.
-- Lee Jones Linaro ST-Ericsson Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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