[Linux-stm32] [PATCH net-next] net: kbuild: Don't default net vendor configs to y

[Jakub Kicinski]

On Mon, 31 Jan 2022 10:40:38 -0800 Florian Fainelli wrote:
> >> And changing the defaults means all defconfigs must be updated first,
> >> else the user's configs will end up without drivers needed.
> >>  
> > 
> > As I understand correctly, at least for most common net drivers, having 
> > NET_VENDOR_XYZ=y doesn't actually build anything, we have flags per
> > module for each vendor and those are defaulted to N.  
> 
> Right, but once you start hiding NET_VENDOR_DRIVER_XYZ under a 
> NET_VENDOR_XYZ Kconfig symbol dependency, if NET_VENDOR_XYZ is not set 
> to Y, then you have no way to select NET_VENDOR_DRIVER_XYZ and so your 
> old defconfig breaks.

To be clear do we actually care about *old* configs or *def* configs?

Breaking defconfigs seems bad, but I don't think we can break
reasonable oldconfigs at this point?

> >> It might make sense to tune some of the defaults (i.e. change to
> >> "default y if ARCH_*") for drivers with clear platform dependencies.
> >>  
> > 
> > either set hard default to 'n' or just keep it as is, anything else is just
> > more confusion.  
> 
> Maybe the rule should go like this: any new driver vendor defaults to n, 
> and existing ones remain set to y, until we deprecate doing that and 
> switching them all off to n by 5.18?

I'd be afraid that given the work of fixing up defconfigs is
non-trivial we may end up never switching old drivers. And then we'd
have a semi-random soup of defaults :(