cvs commit: src/sys/i386/conf DEFAULTS GENERIC

[Scott Long]

Nate Lawson wrote:
> Ceri Davies wrote:
> 
>> On Sat, Oct 29, 2005 at 11:21:48PM -0700, David O'Brien wrote:
>>
>>> On Thu, Oct 27, 2005 at 05:34:35PM +0000, John Baldwin wrote:
>>>
>>>> jhb         2005-10-27 17:34:35 UTC
>>>>
>>>>  FreeBSD src repository
>>>>
>>>>  Modified files:
>>>>    sys/i386/conf        GENERIC  Added files:
>>>>    sys/i386/conf        DEFAULTS  Log:
>>>>  Create a default kernel config for i386 and move 'device isa' and
>>>>  'device npx' (both of which aren't really optional right now) and
>>>>  'device io' and 'device mem' (to preserve POLA for 4.x users upgrading
>>>>  to 6.0) from GENERIC into DEFAULTS.
>>>
>>>
>>> I may be missing something.  I don't quite follow the benefit of the new
>>> 'DEFAULTS' file.  I'm also curious why we don't explicitly 'include'
>>> DEFAULTS in GENERIC vs. the new automagic include feature.
>>
>>
>>
>> I was also confused by that.  There are also no warnings if DEFAULTS is
>> missing, which means that by removing a seemingly unrelated file I get a
>> different (read: useless to me) kernel.  Does INCLUDE_CONFIG_FILE show
>> the contents of DEFAULTS as well?
> 
> 
> A better way would be to make io and mem only compile time options 
> (default to on).  There is no benefit to them being modules.  Anyone who 
> wants to compile with NO_DEVIO or NO_DEVMEM will know why their kernel 
> stops working.
> 

Using options was heavily debated, and I was the actually the proponent
of it.  Then it was pointed out that it would cause headaches for people
moving their kernel configs from 5.x and 6-BETA, since effectively
turning the code from a device to an option would mean that 'device io'
would make config throw an error.

There are things in a kernel config that are either non-optional or
heavily recommended for novice users, so DEFAULTS provides an easy way
to keep the foot shooting to a minimum.  For the power users who are far
too advanced for this, just delete the DEFAULTS file and go on your way.
config will silently ignore it if it's not there.  For those who are 
concerned about cvsup bringing it back automatically, we can look at 
adding a NODEFAULTS directive for your custom config files.  Or, just
use the 'nodevice' and 'nooption' directives to nullify what you don't
like in DEFAULTS.

Scott