On 2021-02-21 16:25, Masahiro Yamada wrote:

You should use KCFLAGS to pass additional compiler flags from the
command line. Using EXTRA_CFLAGS is wrong.

EXTRA_CFLAGS is supposed to specify flags applied only to the current
Makefile (and now deprecated in favor of ccflags-y).

It is still used in arch/mips/kvm/Makefile (and possibly in external
modules too). Passing EXTRA_CFLAGS from the command line overwrites
it and breaks the build.

I also fixed drivers/gpu/drm/tilcdc/Makefile because commit 
816175dd1fd7
("drivers/gpu/drm/tilcdc: Makefile, only -Werror when no -W* in
EXTRA_CFLAGS") was based on the same misunderstanding.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 Documentation/process/4.Coding.rst                            | 2 +-
 Documentation/process/submit-checklist.rst                    | 2 +-
 Documentation/translations/it_IT/process/4.Coding.rst         | 2 +-
 Documentation/translations/it_IT/process/submit-checklist.rst | 2 +-
 Documentation/translations/zh_CN/process/4.Coding.rst         | 2 +-
 drivers/gpu/drm/tilcdc/Makefile                               | 2 +-
 6 files changed, 6 insertions(+), 6 deletions(-)

Acked-by: Federico Vaga <federico.vaga@vaga.pv.it>

-- 
Federico Vaga
http://www.federicovaga.it/