Re: [PATCH] drm/radeon: Add build directory to include path

[Alex Deucher <alexdeucher@gmail.com>]

On Thu, Apr 14, 2022 at 4:44 AM Christian König
<ckoenig.leichtzumerken@gmail.com> wrote:
>
> Am 14.04.22 um 09:37 schrieb Michel Dänzer:
> > On 2022-04-14 08:24, Christian König wrote:
> >> Am 13.04.22 um 18:14 schrieb Michel Dänzer:
> >>> From: Michel Dänzer <mdaenzer@redhat.com>
> >>>
> >>> Fixes compile errors with out-of-tree builds, e.g.
> >>>
> >>> ../drivers/gpu/drm/radeon/r420.c:38:10: fatal error: r420_reg_safe.h: No such file or directory
> >>>      38 | #include "r420_reg_safe.h"
> >>>         |          ^~~~~~~~~~~~~~~~~
> >>
> >> Well stuff like that usually points to a broken build environment.
> > Just a separate build directory. Specifically, I'm hitting the errors with
> >
> >   make -C build-amd64 M=drivers/gpu/drm
> >
> > Generated headers such as r420_reg_safe.h reside in the build directory, so source files in the source directory can't find them without an explicit search path.
>
> I'm trying to swap back into my brain how all of this used to work, but
> that's a really long time ago that I tried this as well.
>
> > Are you saying that should get added automagically somehow?
>
> Yes, exactly that. I'm like 95% sure that used to work, but I don't know
> why exactly either.
>
> > FWIW, this is pretty common in the kernel according to git grep.
>
> Maybe Alex or somebody else with some more background in the kernel
> Makefiles could jump in and help here.

I don't remember either.  I vaguely recall the build support for the
mkregtable stuff being reworked a while ago.  A quick zip through the
git logs shows a series from Masahiro Yamada from 2020.

Alex