Re: linux-next: manual merge of the amdgpu tree with Linus' tree

From: Masahiro Yamada <yamada.masahiro@socionext.com>
To: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Alex Deucher <alexdeucher@gmail.com>,
	Linux Next Mailing List <linux-next@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>
Subject: Re: linux-next: manual merge of the amdgpu tree with Linus' tree
Date: Mon, 28 Oct 2019 10:13:17 +0900	[thread overview]
Message-ID: <CAK7LNAS-k6JnYBqzFHXd5D2LrtF111ch-zqkkCaygTGfKaY5_A@mail.gmail.com> (raw)
In-Reply-To: <20191028115740.791bdeba@canb.auug.org.au>

On Mon, Oct 28, 2019 at 9:57 AM Stephen Rothwell <sfr@canb.auug.org.au> wrote:
>
> Hi all,
>
> Today's linux-next merge of the amdgpu tree got a conflict in:
>
>   drivers/gpu/drm/amd/display/dc/dcn20/Makefile
>
> between commit:
>
>   54b8ae66ae1a ("kbuild: change *FLAGS_<basetarget>.o to take the path relative to $(obj)")
>
> from Linus' tree and commits:
>
>   4f952528add3 ("drm/amdgpu: fix stack alignment ABI mismatch for Clang")
>   971463bea55c ("drm/amdgpu: fix stack alignment ABI mismatch for GCC 7.1+")
>   101d09f07966 ("drm/amdgpu: enable -msse2 for GCC 7.1+ users")
>
> from the amdgpu tree.
>
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging.  You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.

I believe subsystems should queue up patches
against -rc1 or a later tag.

Developing based on an older version
causes unneeded conflicts like this.

> --
> Cheers,
> Stephen Rothwell
>
> diff --cc drivers/gpu/drm/amd/display/dc/dcn20/Makefile
> index ddb8d5649e79,be3a614963c6..000000000000
> --- a/drivers/gpu/drm/amd/display/dc/dcn20/Makefile
> +++ b/drivers/gpu/drm/amd/display/dc/dcn20/Makefile
> @@@ -10,16 -10,21 +10,21 @@@ ifdef CONFIG_DRM_AMD_DC_DSC_SUPPOR
>   DCN20 += dcn20_dsc.o
>   endif
>
> - ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)
> -       cc_stack_align := -mpreferred-stack-boundary=4
> - else ifneq ($(call cc-option, -mstack-alignment=16),)
> -       cc_stack_align := -mstack-alignment=16
> - endif
>  -CFLAGS_dcn20_resource.o := -mhard-float -msse
> ++CFLAGS_$(AMDDALPATH)/dc/dcn20/dcn20_resource.o := -mhard-float -msse
>
> - CFLAGS_$(AMDDALPATH)/dc/dcn20/dcn20_resource.o := -mhard-float -msse $(cc_stack_align)
> + ifdef CONFIG_CC_IS_GCC
> + ifeq ($(call cc-ifversion, -lt, 0701, y), y)
> + IS_OLD_GCC = 1
> + endif
> + endif
>
> - ifdef CONFIG_CC_IS_CLANG
> + ifdef IS_OLD_GCC
> + # Stack alignment mismatch, proceed with caution.
> + # GCC < 7.1 cannot compile code using `double` and -mpreferred-stack-boundary=3
> + # (8B stack alignment).
>  -CFLAGS_dcn20_resource.o += -mpreferred-stack-boundary=4
> ++CFLAGS_$(AMDDALPATH)/dc/dcn20/dcn20_resource.o += -mpreferred-stack-boundary=4
> + else
>  -CFLAGS_dcn20_resource.o += -msse2
>  +CFLAGS_$(AMDDALPATH)/dc/dcn20/dcn20_resource.o += -msse2
>   endif
>
>   AMD_DAL_DCN20 = $(addprefix $(AMDDALPATH)/dc/dcn20/,$(DCN20))

-- 
Best Regards
Masahiro Yamada