Re: [PATCH 1/4] drm/amdgpu: Treat warning as an error

["Michel Dänzer" <michel.daenzer@mailbox.org>]

On 2022-01-11 00:39, Rodrigo Siqueira wrote:
> We have one internal CI that builds our kernel with the -Werror flag; as
> a result, when we try to sync our branch with amd-staging-drm-next we
> get some failures due to warnings. This commit tries to alleviate this
> problem by forcing a warning to be treated as an error.
> 
> Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/Makefile | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/Makefile b/drivers/gpu/drm/amd/amdgpu/Makefile
> index 7fedbb725e17..158f427c2f2e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/Makefile
> +++ b/drivers/gpu/drm/amd/amdgpu/Makefile
> @@ -27,6 +27,8 @@ FULL_AMD_PATH=$(srctree)/$(src)/..
>  DISPLAY_FOLDER_NAME=display
>  FULL_AMD_DISPLAY_PATH = $(FULL_AMD_PATH)/$(DISPLAY_FOLDER_NAME)
>  
> +subdir-ccflags-y += -Werror

The problem with this is that different compilers, or even different versions of the same compiler, can generate different warnings for the same code. So this will definitely result in some people hitting compile failures for no reason other than using a different compiler (version) than the code had been tested with. Or maybe just a different .config.

Unless you secretly hate your users ;) [0], I'd strongly recommend against enabling this unconditionally.

(The proper place for -Werror is in CI which gates merging of all changes. E.g. Mesa's upstream GitLab CI does this with great success)


[0] No, this isn't about RHEL — the RHEL kernel build always enables -Werror, so we need to deal with that anyway.

-- 
Earthling Michel Dänzer            |                  https://redhat.com
Libre software enthusiast          |         Mesa and Xwayland developer