Subject: [PATCH 5.4 9/9] drm/amd/display: Do not add '-mhard-float' to dcn2{1,0}_resource.o for clang

From: Nathan Chancellor <[email-masked]>
Date: Wed, 4 Jun 2025 14:08:09 -0700

This patch is for linux-5.15.y and earlier only. It is functionally
equivalent to upstream commit 7db038d9790e ("drm/amd/display: Do not add
'-mhard-float' to dml_ccflags for clang"), which was created after all
files that require '-mhard-float' were moved under the dml folder. In
kernels older than 5.18, which do not contain upstream commits

  22f87d998326 ("drm/amd/display: move FPU operations from dcn21 to dml/dcn20 folder")
  cf689e869cf0 ("drm/amd/display: move FPU-related code from dcn20 to dml folder")

newer versions of clang error with

  clang: error: unsupported option '-mhard-float' for target 'x86_64-linux-gnu'
  make[6]: *** [scripts/Makefile.build:289: drivers/gpu/drm/amd/amdgpu/../display/dc/dcn20/dcn20_resource.o] Error 1
  clang: error: unsupported option '-mhard-float' for target 'x86_64-linux-gnu'
  make[6]: *** [scripts/Makefile.build:289: drivers/gpu/drm/amd/amdgpu/../display/dc/dcn21/dcn21_resource.o] Error 1

Apply a functionally equivalent change to prevent adding '-mhard-float'
with clang for these files.

Signed-off-by: Nathan Chancellor <[email-masked]>
---
 drivers/gpu/drm/amd/display/dc/dcn20/Makefile | 2 +-
 drivers/gpu/drm/amd/display/dc/dcn21/Makefile | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/Makefile b/drivers/gpu/drm/amd/display/dc/dcn20/Makefile
index 63f3bddba7da..9b5da78a950d 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn20/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/dcn20/Makefile
@@ -10,7 +10,7 @@ ifdef CONFIG_DRM_AMD_DC_DSC_SUPPORT
 DCN20 += dcn20_dsc.o
 endif
 
-CFLAGS_$(AMDDALPATH)/dc/dcn20/dcn20_resource.o := -mhard-float -msse
+CFLAGS_$(AMDDALPATH)/dc/dcn20/dcn20_resource.o := $(if $(CONFIG_CC_IS_GCC), -mhard-float) -msse
 
 ifdef CONFIG_CC_IS_GCC
 ifeq ($(call cc-ifversion, -lt, 0701, y), y)
diff --git a/drivers/gpu/drm/amd/display/dc/dcn21/Makefile b/drivers/gpu/drm/amd/display/dc/dcn21/Makefile
index ff50ae71fe27..a73dd11654de 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn21/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/dcn21/Makefile
@@ -3,7 +3,7 @@
 
 DCN21 = dcn21_hubp.o dcn21_hubbub.o dcn21_resource.o
 
-CFLAGS_$(AMDDALPATH)/dc/dcn21/dcn21_resource.o := -mhard-float -msse
+CFLAGS_$(AMDDALPATH)/dc/dcn21/dcn21_resource.o := $(if $(CONFIG_CC_IS_GCC), -mhard-float) -msse
 
 ifdef CONFIG_CC_IS_GCC
 ifeq ($(call cc-ifversion, -lt, 0701, y), y)
-- 
2.49.0