On Wed, Jul 28, 2021 at 09:04:34AM +0200, Arnd Bergmann wrote: > On Wed, Jul 28, 2021 at 7:43 AM Christoph Hellwig <hch@xxxxxx> wrote: > > > > On Tue, Jul 27, 2021 at 08:09:41PM -0300, Jason Gunthorpe wrote: > > > On Tue, Jul 27, 2021 at 03:54:40PM -0600, Alex Williamson wrote: > > > > > > > I'm still not happy with how this is likely to break users and even > > > > downstreams when upgrading to a Kconfig with this change. > > > > > > I've never heard of Kconfig as stable ABI. Christoph/Arnd, have you > > > heard of any cases where we want to keep it stable? > > > > It isn't an ABI, but we really do try to avoid breaking if we can and > > I rember Linus shouting at people if they did that for common options. > > This is handled in very different ways depending on the maintainers, > some people go to great lengths to avoid breaking 'make oldconfig' > or 'make defconfig', others don't seem to mind at all. > > CONFIG_USB_EHCI_TEGRA is an example of an option that was > left in place to help users of old config files, another one is > CONFIG_EXT3_FS. In both cases the idea is that the original > code was changed, but the old option left in place to point to > the replacement. And here starts the problem, when people treat their obscure config options as first class citizen. The exposure of CONFIG_EXT3_FS is in magnitudes larger than CONFIG_USB_EHCI_TEGRA. This is why I think that is generally bad idea to leave old config options, most of the time such options will rotten for years till someone actually will notice and delete them. Thanks
