[PATCH] drm: Hack around CONFIG_AGP=m build failures

[Michal Marek]

On 2015-10-01 16:50, Michal Marek wrote:
> On 2015-10-01 12:17, Daniel Vetter wrote:
>> On Thu, Oct 01, 2015 at 11:58:32AM +0200, Michal Marek wrote:
>>> On 2015-10-01 10:19, Jani Nikula wrote:
>>>> On Thu, 01 Oct 2015, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
>>>>> Surprisingly kbuild can't cope with tristates in the
>>>>> <module>-$(CONFIG_FOO) pattern. This patch hacks up a solution.
>>>>
>>>> Given that it's two distinct Makefile variables (foo-y and foo-m) being
>>>> assigned to, I don't really find this surprising. Maybe this could be
>>>> made to work as a convenience, but there might be other, more surpising
>>>> consequences.
>>>
>>> I actually think that kbuild should be able to handle this. The likely
>>> reason why it is not doing it right now is that in an ideal world,
>>> modules are modules can be built out of tree against just the kernel and
>>> their static dependencies. In real world, we sometimes have features in
>>> modules that are enabled if other modules are enabled. I'll post a patch
>>> later. We also have lots of tests fo CONFIG_FOO || CONFIG_FOO_MODULE in
>>> built-in code, which is a similar case.
>>
>> Cool. I'll keep this hack in drm-misc then. Please cc me on the proper
>> solution so I know when I can revert it again.
> 
> It's not as trivial as it seemed, because there are at least three
> Makefiles that rely on the current behavior:
> 
> init/Makefile
> drivers/misc/ibmasm/Makefile
> fs/logfs/Makefile

drivers/usb/chipidea is also on the list.

Michal