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, 315 insertions, 0 deletions

diff --git a/scripts/dev-needs.sh b/scripts/dev-needs.sh
new file mode 100755
index 000000000..454cc304f
--- /dev/null
+++ b/scripts/dev-needs.sh
@@ -0,0 +1,315 @@
+#! /bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2020, Google LLC. All rights reserved.
+# Author: Saravana Kannan <saravanak@google.com>
+
+function help() {
+	cat << EOF
+Usage: $(basename $0) [-c|-d|-m|-f] [filter options] <list of devices>
+
+This script needs to be run on the target device once it has booted to a
+shell.
+
+The script takes as input a list of one or more device directories under
+/sys/devices and then lists the probe dependency chain (suppliers and
+parents) of these devices. It does a breadth first search of the dependency
+chain, so the last entry in the output is close to the root of the
+dependency chain.
+
+By default it lists the full path to the devices under /sys/devices.
+
+It also takes an optional modifier flag as the first parameter to change
+what information is listed in the output. If the requested information is
+not available, the device name is printed.
+
+  -c	lists the compatible string of the dependencies
+  -d	lists the driver name of the dependencies that have probed
+  -m	lists the module name of the dependencies that have a module
+  -f	list the firmware node path of the dependencies
+  -g	list the dependencies as edges and nodes for graphviz
+  -t	list the dependencies as edges for tsort
+
+The filter options provide a way to filter out some dependencies:
+  --allow-no-driver	By default dependencies that don't have a driver
+			attached are ignored. This is to avoid following
+			device links to "class" devices that are created
+			when the consumer probes (as in, not a probe
+			dependency). If you want to follow these links
+			anyway, use this flag.
+
+  --exclude-devlinks	Don't follow device links when tracking probe
+			dependencies.
+
+  --exclude-parents	Don't follow parent devices when tracking probe
+			dependencies.
+
+EOF
+}
+
+function dev_to_detail() {
+	local i=0
+	while [ $i -lt ${#OUT_LIST[@]} ]
+	do
+		local C=${OUT_LIST[i]}
+		local S=${OUT_LIST[i+1]}
+		local D="'$(detail_chosen $C $S)'"
+		if [ ! -z "$D" ]
+		then
+			# This weirdness is needed to work with toybox when
+			# using the -t option.
+			printf '%05u\t%s\n' ${i} "$D" | tr -d \'
+		fi
+		i=$((i+2))
+	done
+}
+
+function already_seen() {
+	local i=0
+	while [ $i -lt ${#OUT_LIST[@]} ]
+	do
+		if [ "$1" = "${OUT_LIST[$i]}" ]
+		then
+			# if-statement treats 0 (no-error) as true
+			return 0
+		fi
+		i=$(($i+2))
+	done
+
+	# if-statement treats 1 (error) as false
+	return 1
+}
+
+# Return 0 (no-error/true) if parent was added
+function add_parent() {
+
+	if [ ${ALLOW_PARENTS} -eq 0 ]
+	then
+		return 1
+	fi
+
+	local CON=$1
+	# $CON could be a symlink path. So, we need to find the real path and
+	# then go up one level to find the real parent.
+	local PARENT=$(realpath $CON/..)
+
+	while [ ! -e ${PARENT}/driver ]
+	do
+		if [ "$PARENT" = "/sys/devices" ]
+		then
+			return 1
+		fi
+		PARENT=$(realpath $PARENT/..)
+	done
+
+	CONSUMERS+=($PARENT)
+	OUT_LIST+=(${CON} ${PARENT})
+	return 0
+}
+
+# Return 0 (no-error/true) if one or more suppliers were added
+function add_suppliers() {
+	local CON=$1
+	local RET=1
+
+	if [ ${ALLOW_DEVLINKS} -eq 0 ]
+	then
+		return 1
+	fi
+
+	SUPPLIER_LINKS=$(ls -1d $CON/supplier:* 2>/dev/null)
+	for SL in $SUPPLIER_LINKS;
+	do
+		SYNC_STATE=$(cat $SL/sync_state_only)
+
+		# sync_state_only links are proxy dependencies.
+		# They can also have cycles. So, don't follow them.
+		if [ "$SYNC_STATE" != '0' ]
+		then
+			continue
+		fi
+
+		SUPPLIER=$(realpath $SL/supplier)
+
+		if [ ! -e $SUPPLIER/driver -a ${ALLOW_NO_DRIVER} -eq 0 ]
+		then
+			continue
+		fi
+
+		CONSUMERS+=($SUPPLIER)
+		OUT_LIST+=(${CON} ${SUPPLIER})
+		RET=0
+	done
+
+	return $RET
+}
+
+function detail_compat() {
+	f=$1/of_node/compatible
+	if [ -e $f ]
+	then
+		echo -n $(cat $f)
+	else
+		echo -n $1
+	fi
+}
+
+function detail_module() {
+	f=$1/driver/module
+	if [ -e $f ]
+	then
+		echo -n $(basename $(realpath $f))
+	else
+		echo -n $1
+	fi
+}
+
+function detail_driver() {
+	f=$1/driver
+	if [ -e $f ]
+	then
+		echo -n $(basename $(realpath $f))
+	else
+		echo -n $1
+	fi
+}
+
+function detail_fwnode() {
+	f=$1/firmware_node
+	if [ ! -e $f ]
+	then
+		f=$1/of_node
+	fi
+
+	if [ -e $f ]
+	then
+		echo -n $(realpath $f)
+	else
+		echo -n $1
+	fi
+}
+
+function detail_graphviz() {
+	if [ "$2" != "ROOT" ]
+	then
+		echo -n "\"$(basename $2)\"->\"$(basename $1)\""
+	else
+		echo -n "\"$(basename $1)\""
+	fi
+}
+
+function detail_tsort() {
+	echo -n "\"$2\" \"$1\""
+}
+
+function detail_device() { echo -n $1; }
+
+alias detail=detail_device
+ALLOW_NO_DRIVER=0
+ALLOW_DEVLINKS=1
+ALLOW_PARENTS=1
+
+while [ $# -gt 0 ]
+do
+	ARG=$1
+	case $ARG in
+		--help)
+			help
+			exit 0
+			;;
+		-c)
+			alias detail=detail_compat
+			;;
+		-m)
+			alias detail=detail_module
+			;;
+		-d)
+			alias detail=detail_driver
+			;;
+		-f)
+			alias detail=detail_fwnode
+			;;
+		-g)
+			alias detail=detail_graphviz
+			;;
+		-t)
+			alias detail=detail_tsort
+			;;
+		--allow-no-driver)
+			ALLOW_NO_DRIVER=1
+			;;
+		--exclude-devlinks)
+			ALLOW_DEVLINKS=0
+			;;
+		--exclude-parents)
+			ALLOW_PARENTS=0
+			;;
+		*)
+			# Stop at the first argument that's not an option.
+			break
+			;;
+	esac
+	shift
+done
+
+function detail_chosen() {
+	detail $1 $2
+}
+
+if [ $# -eq 0 ]
+then
+	help
+	exit 1
+fi
+
+CONSUMERS=($@)
+OUT_LIST=()
+
+# Do a breadth first, non-recursive tracking of suppliers. The parent is also
+# considered a "supplier" as a device can't probe without its parent.
+i=0
+while [ $i -lt ${#CONSUMERS[@]} ]
+do
+	CONSUMER=$(realpath ${CONSUMERS[$i]})
+	i=$(($i+1))
+
+	if already_seen ${CONSUMER}
+	then
+		continue
+	fi
+
+	# If this is not a device with a driver, we don't care about its
+	# suppliers.
+	if [ ! -e ${CONSUMER}/driver -a ${ALLOW_NO_DRIVER} -eq 0 ]
+	then
+		continue
+	fi
+
+	ROOT=1
+
+	# Add suppliers to CONSUMERS list and output the consumer details.
+	#
+	# We don't need to worry about a cycle in the dependency chain causing
+	# infinite loops. That's because the kernel doesn't allow cycles in
+	# device links unless it's a sync_state_only device link. And we ignore
+	# sync_state_only device links inside add_suppliers.
+	if add_suppliers ${CONSUMER}
+	then
+		ROOT=0
+	fi
+
+	if add_parent ${CONSUMER}
+	then
+		ROOT=0
+	fi
+
+	if [ $ROOT -eq 1 ]
+	then
+		OUT_LIST+=(${CONSUMER} "ROOT")
+	fi
+done
+
+# Can NOT combine sort and uniq using sort -suk2 because stable sort in toybox
+# isn't really stable.
+dev_to_detail | sort -k2 -k1 | uniq -f 1 | sort | cut -f2-
+
+exit 0