Re: HEADSUP: drm-current-kmod now installs sources

On 8/14/19 1:19 PM, Ian Lepore wrote:
> On Wed, 2019-08-14 at 13:59 -0600, Warner Losh wrote:
>> On Wed, Aug 14, 2019 at 1:56 PM Ian Lepore <ian_at_freebsd.org> wrote:
>>
>>> On Wed, 2019-08-14 at 12:00 -0700, John Baldwin wrote:
>>>> On 8/14/19 11:06 AM, Kyle Evans wrote:
>>>>> LOCAL_MODULES="" does seem like a sensible default when we're
>>>>> not
>>>>> building a native kernel.
>>>>
>>>> Unfortunately kern.post.mk has no way of knowing that as
>>>> MACHINE_*
>>>> are already set to the TARGET_* values by the time this target is
>>>> invoked.  Also, the 'make tinderbox' use case is a legit use case
>>>> that some folks want (for CI, etc.)
>>>>
>>>
>>> BUILDHOST_ARCH!= uname -p
>>> .if ${BUILDHOST_ARCH} != ${TARGET_ARCH}
>>>
>>> Unfortunately, I don't think it's as easy to compare the buildhost
>>> running version with the version of source being built, unless the
>>> build is started from the top level so that Makefile.inc1 sets the
>>> variables.
>>>
>>
>> We already know MACHINE_ARCH != TARGET_ARCH in Makefile.inc1 and
>> already do
>> different things based on it. But to be honest, I'd think there'd be
>> times
>> I'd absolutely want to build them all, and other times I wouldn't
>> which
>> strongly suggests some kind of knob specific for cross building the
>> port/pkg-based kernel modules. We could then pass that knob into the
>> kernel
>> builds which would then not try to guess whether or not to build
>> LOCAL_MODULES...
>>
>>
> 
> This is just about AUTOMATICALLY deciding to build something, based on
> the presence of source code in an arbitrary fixed location outside of
> the source tree on the build machine.  Anything set by the user should
> be honored without question, including LOCAL_MODULES.  
> 
> My point is only that the build machinery should not be deciding to
> build something the user didn't specify based on the existence of out-
> of-tree files on the build machine (I'd like to put the period right
> here in this sentence), unless there's a very high likelyhood that the
> build being done is for the build machine.
> 
> Things like CI that want to include more than in-tree sources as part
> of the build should be handling that by setting appropriate knobs as
> part of invoking the build.

I talked with Warner some offline and I think having some knob that
controls whether or not LOCAL_MODULES auto-populates and having make
buildkernel default it to on/off for native/cross builds (but it can
always be forcefully set on the command line) is fine with me.

-- 
John Baldwin