[PATCH 4/6] drm/amd/display: fix dcn21 Makefile for clang

[Alex Deucher]

On Wed, Oct 2, 2019 at 10:51 AM Arnd Bergmann <arnd at arndb.de> wrote:
>
> On Wed, Oct 2, 2019 at 4:17 PM Alex Deucher <alexdeucher at gmail.com> wrote:
> >
> > I'm getting an error with gcc with this patch:
> >   CC [M]  drivers/gpu/drm/amd/amdgpu/../display/dc/dcn21/dcn21_resource.o
> > drivers/gpu/drm/amd/amdgpu/../display/dc/dcn21/dcn21_resource.c: In
> > function ‘calculate_wm_set_for_vlevel’:
> > drivers/gpu/drm/amd/amdgpu/../display/dc/dcn21/dcn21_resource.c:964:22:
> > error: SSE register return with SSE disabled
>
> I checked again with gcc-8, but do not see that error message.
>
> > > -CFLAGS_$(AMDDALPATH)/dc/dcn21/dcn21_resource.o := -mhard-float -msse -mpreferred-stack-boundary=4
> > > +CFLAGS_$(AMDDALPATH)/dc/dcn21/dcn21_resource.o := -mhard-float -msse $(cc_stack_align)
>
> Nothing should really change with regards to the -msse flag here, only
> the stack alignment flag changed. Maybe there was some other change
> in your Makefile that conflicts with my my patch?

This patch on top of yours seems to fix it and aligns better with the
other Makefiles:

diff --git a/drivers/gpu/drm/amd/display/dc/dcn21/Makefile
b/drivers/gpu/drm/amd/display/dc/dcn21/Makefile
index ef673bffc241..e71f3ee76cd1 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn21/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/dcn21/Makefile
@@ -9,10 +9,10 @@ else ifneq ($(call cc-option, -mstack-alignment=16),)
        cc_stack_align := -mstack-alignment=16
 endif

-CFLAGS_$(AMDDALPATH)/dc/dcn21/dcn21_resource.o := -mhard-float -msse
$(cc_stack_align)
+CFLAGS_dcn21_resource.o := -mhard-float -msse $(cc_stack_align)

 ifdef CONFIG_CC_IS_CLANG
-CFLAGS_$(AMDDALPATH)/dc/dcn21/dcn21_resource.o += -msse2
+CFLAGS_dcn21_resource.o += -msse2
 endif

 AMD_DAL_DCN21 = $(addprefix $(AMDDALPATH)/dc/dcn21/,$(DCN21))