Re: lua(4), non-invasive and invasive parts

[Marc Balmer <marc%msys.ch@localhost>]

Am 28.12.2012 um 11:43 schrieb Jukka Ruohonen <jruohonen%iki.fi@localhost>:

> On Fri, Dec 28, 2012 at 11:35:05AM +0100, Marc Balmer wrote:
>>> What does this mean? Also the kernel modules using lua(4) will be
>>> conditionally compiled? I think this is fairly strongly against the design
>>> principles of module(7).
>> 
>> This means that gpiosim(4) can be compiled with Lua support, if 'options
>> LUA' is defined in the kernel configuration.  As Lua in the kernel is
>> experimental, such a guard makes sense.
> 
> I think this has been discussed previously, the conclusion being that kernel
> modules should not diverge upon changes in the kernel configuration options. 
> 
> The practical case is: what happens when I try to load gpiosim(4) after
> having compiled a kernel with a LUA option but not having updated
> userland/modules (or vice versa)?


No harm done.

A gpiosim(4) module compiled without lua(4) support will just work (if gpio(4) 
support is present), a gpiosim(4) module compiled *with* lua(4) support will 
try to load the gpio(4) module and the lua(4) module, and if either fails it 
will itself not load.