[OE-core] [PATCH] kernel: use oldnoconfig instead of yes '' | make oldconfig
Alexandre Belloni
alexandre.belloni at free-electrons.com
Tue Jan 7 20:27:40 UTC 2014
On 07/01/2014 16:32, Bruce Ashfield wrote:
> On 14-01-07 09:18 AM, Alexandre Belloni wrote:
>> When using a defconfig, using yes '' | make oldconfig may not result in
>> the correct configuration being set. For example:
>>
>> $ grep USB_ETH .config
>> CONFIG_USB_ETH=y
>> CONFIG_USB_ETH_RNDIS=y
>> CONFIG_USB_ETH_EEM=y
>> $ make savedefconfig
>> scripts/kconfig/conf --savedefconfig=defconfig Kconfig
>> $ cp defconfig .config
>> ‘defconfig’ -> ‘.config’
>> $ yes '' | make oldconfig
>> [...]
>> #
>> # configuration written to .config
>> #
>> $ grep USB_ETH .config
>> CONFIG_USB_ETH=m
>> CONFIG_USB_ETH_RNDIS=y
>> CONFIG_USB_ETH_EEM=y
>>
>> Using make olddefconfig solves that but we'll use oldnoconfig for
>> backward compatibility with older kernels.
>>
>> $ cp defconfig .config
>> ‘defconfig’ -> ‘.config’
>> $ make oldnoconfig
>> scripts/kconfig/conf --olddefconfig Kconfig
>> #
>> # configuration written to .config
>> #
>> $ grep USB_ETH .config
>> CONFIG_USB_ETH=y
>> CONFIG_USB_ETH_RNDIS=y
>> CONFIG_USB_ETH_EEM=y
>>
>> For more information, please refer to:
>> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=fbe98bb9ed3dae23e320c6b113e35f129538d14a
>>
>
> It was my understanding that this commit changed the Kconfig behaviour
> to set the selected options to =y and prevent the menu choice from
> "hiding" the options in a depedent choice menu. But maybe I'm remembering
> wrong.
>
> The point being, that with that commit in place. Doesn't the behaviour
> match what we want with yes and oldconfig ?
>
Nope, that commit is fixing the issue when using make <target>_defconfig
or make olddefconfig. Note that using make menuconfig already had the
correct behavior before that commit.
As shown in my commit log, using yes '' | make oldconfig is still
getting it wrong.
> .. I'll run some tests to confirm for myself, but I thought I'd throw
> the question out as well. I don't typically use defconfigs, so I need
> to do a bit of leg work.
>
Yeah, using a full .config doesn't trigger that behavior.
> I don't have any big issues with the patch, but I just want to be sure,
> since changing this default could change the configs of many defconfig
> users, and they may have been unknowingly relying on the old behaviour.
>
I can understand that. But I don't see any other way to make the really
expected behavior to work without risking breaking anything.
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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