drm/amd/display: Try RGB before YCbCr 4:4:4 in stream validationgrafted

amdgpu_dm_create_validate_stream_for_sink() walks encoding_order[] and
uses the first encoding that validates. YCbCr 4:4:4 is listed before
RGB, so an HDMI sink that advertises 4:4:4 gets YCbCr 4:4:4 whenever the
"color format" property is left at AUTO, even though RGB fits the same
link.

That contradicts the documented AUTO behaviour for HDMI in enum
drm_connector_color_format (RGB, falling back to YCbCr 4:2:0 only when
the bandwidth is not available or the mode is 4:2:0-only), which the
amdgpu implementation of the property also describes. It also leaves
the "Broadcast RGB" property without effect on such sinks, since the
quantization range it selects only applies to RGB output.

Try RGB first. The mask still holds every encoding the sink supports,
so a mode that cannot carry RGB falls back exactly as before.

For reference, v7.2 picked RGB here unless YCbCr 4:4:4 was forced
through debugfs, while earlier kernels picked YCbCr 4:4:4 for any HDMI
sink that advertised it.

Fixes: 0b0ff65d3ca1 ("drm/amd/display: Refactor stream validation")
Suggested-by: Adolfo Rodrigues <adolfotregosa@gmail.com>
Assisted-by: Claude Code:claude-fable-5-1
Signed-off-by: Adrian Betschart <adrian.betschart@cinemaone.ch>
Reviewed-by: Fangzhi Zuo <jerry.zuo@amd.com>
Tested-by: Adolfo Rodrigues <adolfotregosa@gmail.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 7de432bc753133764dc40d37f9388da56de251e7)

1 files changed, 105 insertions, 0 deletions

diff --git a/scripts/Makefile.asm-headers b/scripts/Makefile.asm-headers
new file mode 100644
index 000000000..f1c3d287c
--- /dev/null
+++ b/scripts/Makefile.asm-headers
@@ -0,0 +1,105 @@
+# SPDX-License-Identifier: GPL-2.0
+# include/asm-generic contains a lot of files that are used
+# verbatim by several architectures.
+#
+# This Makefile generates arch/$(SRCARCH)/include/generated/(uapi/)/asm
+# headers from multiple sources:
+#  - a small wrapper to include the corresponding asm-generic/*.h
+#    is generated for each file listed as generic-y
+#  - uapi/asm/unistd_*.h files listed as syscalls-y are generated from
+#    syscall.tbl with the __NR_* macros
+#  - Corresponding asm/syscall_table_*.h are generated from the same input
+
+PHONY := all
+all:
+
+src := $(srctree)/$(subst /generated,,$(obj))
+
+syscall_abis_32  += common,32
+syscall_abis_64  += common,64
+syscalltbl := $(srctree)/scripts/syscall.tbl
+syshdr-args := --emit-nr
+
+# let architectures override $(syscall_abis_%) and $(syscalltbl)
+-include $(srctree)/arch/$(SRCARCH)/kernel/Makefile.syscalls
+include $(srctree)/scripts/Kbuild.include
+-include $(kbuild-file)
+
+syshdr := $(srctree)/scripts/syscallhdr.sh
+systbl := $(srctree)/scripts/syscalltbl.sh
+
+# $(generic)/Kbuild lists mandatory-y. Exclude um since it is a special case.
+ifneq ($(SRCARCH),um)
+include $(srctree)/$(generic)/Kbuild
+endif
+
+redundant := $(filter $(mandatory-y) $(generated-y), $(generic-y))
+redundant += $(foreach f, $(generic-y), $(if $(wildcard $(src)/$(f)),$(f)))
+redundant := $(sort $(redundant))
+$(if $(redundant),\
+	$(warning redundant generic-y found in $(src)/Kbuild: $(redundant)))
+
+# If arch does not implement mandatory headers, fallback to asm-generic ones.
+mandatory-y := $(filter-out $(generated-y), $(mandatory-y))
+generic-y   += $(foreach f, $(mandatory-y), $(if $(wildcard $(src)/$(f)),,$(f)))
+
+generic-y   := $(addprefix $(obj)/, $(generic-y))
+syscall-y   := $(addprefix $(obj)/, $(syscall-y))
+generated-y := $(addprefix $(obj)/, $(generated-y))
+
+# Remove stale wrappers when the corresponding files are removed from generic-y
+old-headers := $(shell test -d $(obj) && find $(obj) -name '*.h' ! -name '.*')
+unwanted    := $(filter-out $(generic-y) $(generated-y) $(syscall-y),$(old-headers))
+
+filechk_wrap = echo "\#include <asm-generic/$*.h>"
+
+quiet_cmd_remove = REMOVE  $(unwanted)
+      cmd_remove = rm -f $(unwanted); find $(obj) -type d -empty -delete
+
+quiet_cmd_syshdr = SYSHDR  $@
+      cmd_syshdr = $(CONFIG_SHELL) $(syshdr) \
+		   $(if $(syshdr-args-$*),$(syshdr-args-$*),$(syshdr-args)) \
+		   $(if $(syscall_compat),--prefix "compat$*_") \
+		   --abis $(subst $(space),$(comma),$(strip $(syscall_abis_$*))) \
+		   $< $@
+
+quiet_cmd_systbl = SYSTBL  $@
+      cmd_systbl = $(CONFIG_SHELL) $(systbl) \
+		   $(if $(systbl-args-$*),$(systbl-args-$*),$(systbl-args)) \
+		   --abis $(subst $(space),$(comma),$(strip $(syscall_abis_$*))) \
+		   $< $@
+
+all: $(generic-y) $(syscall-y)
+	$(if $(unwanted),$(call cmd,remove))
+	@:
+
+$(obj)/%.h: $(srctree)/$(generic)/%.h FORCE
+	$(call filechk,wrap)
+
+$(obj)/unistd_%.h: $(syscalltbl) $(syshdr) FORCE
+	$(call if_changed,syshdr)
+
+$(obj)/unistd_compat_%.h: syscall_compat:=1
+$(obj)/unistd_compat_%.h: $(syscalltbl) $(syshdr) FORCE
+	$(call if_changed,syshdr)
+
+$(obj)/syscall_table_%.h: $(syscalltbl) $(systbl) FORCE
+	$(call if_changed,systbl)
+
+targets := $(syscall-y)
+
+# Create output directory. Skip it if at least one old header exists
+# since we know the output directory already exists.
+ifeq ($(old-headers),)
+$(shell mkdir -p $(obj))
+endif
+
+PHONY += FORCE
+
+FORCE:
+
+existing-targets := $(wildcard $(sort $(targets)))
+
+-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
+
+.PHONY: $(PHONY)