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, 193 insertions, 0 deletions

diff --git a/scripts/headerdep.pl b/scripts/headerdep.pl
new file mode 100755
index 000000000..ebfcbef43
--- /dev/null
+++ b/scripts/headerdep.pl
@@ -0,0 +1,193 @@
+#! /usr/bin/env perl
+# SPDX-License-Identifier: GPL-2.0
+#
+# Detect cycles in the header file dependency graph
+# Vegard Nossum <vegardno@ifi.uio.no>
+#
+
+use strict;
+use warnings;
+
+use Getopt::Long;
+
+my $opt_all;
+my @opt_include;
+my $opt_graph;
+
+&Getopt::Long::Configure(qw(bundling pass_through));
+&GetOptions(
+	help	=> \&help,
+	version	=> \&version,
+
+	all	=> \$opt_all,
+	"I=s"	=> \@opt_include,
+	graph	=> \$opt_graph,
+);
+
+push @opt_include, 'include';
+my %deps = ();
+my %linenos = ();
+
+my @headers = grep { strip($_) } @ARGV;
+
+parse_all(@headers);
+
+if($opt_graph) {
+	graph();
+} else {
+	detect_cycles(@headers);
+}
+
+
+sub help {
+	print "Usage: $0 [options] file...\n";
+	print "\n";
+	print "Options:\n";
+	print "  --all\n";
+	print "  --graph\n";
+	print "\n";
+	print "  -I includedir\n";
+	print "\n";
+	print "To make nice graphs, try:\n";
+	print "  $0 --graph include/linux/kernel.h | dot -Tpng -o graph.png\n";
+	exit;
+}
+
+sub version {
+	print "headerdep version 2\n";
+	exit;
+}
+
+# Get a file name that is relative to our include paths
+sub strip {
+	my $filename = shift;
+
+	for my $i (@opt_include) {
+		my $stripped = $filename;
+		$stripped =~ s/^$i\///;
+
+		return $stripped if $stripped ne $filename;
+	}
+
+	return $filename;
+}
+
+# Search for the file name in the list of include paths
+sub search {
+	my $filename = shift;
+	return $filename if -f $filename;
+
+	for my $i (@opt_include) {
+		my $path = "$i/$filename";
+		return $path if -f $path;
+	}
+	return;
+}
+
+sub parse_all {
+	# Parse all the headers.
+	my @queue = @_;
+	while(@queue) {
+		my $header = pop @queue;
+		next if exists $deps{$header};
+
+		$deps{$header} = [] unless exists $deps{$header};
+
+		my $path = search($header);
+		next unless $path;
+
+		open(my $file, '<', $path) or die($!);
+		chomp(my @lines = <$file>);
+		close($file);
+
+		for my $i (0 .. $#lines) {
+			my $line = $lines[$i];
+			if(my($dep) = ($line =~ m/^#\s*include\s*<(.*?)>/)) {
+				push @queue, $dep;
+				push @{$deps{$header}}, [$i + 1, $dep];
+			}
+		}
+	}
+}
+
+sub print_cycle {
+	# $cycle[n] includes $cycle[n + 1];
+	# $cycle[-1] will be the culprit
+	my $cycle = shift;
+
+	# Adjust the line numbers
+	for my $i (0 .. $#$cycle - 1) {
+		$cycle->[$i]->[0] = $cycle->[$i + 1]->[0];
+	}
+	$cycle->[-1]->[0] = 0;
+
+	my $first = shift @$cycle;
+	my $last = pop @$cycle;
+
+	my $msg = "In file included";
+	printf "%s from %s,\n", $msg, $last->[1] if defined $last;
+
+	for my $header (reverse @$cycle) {
+		printf "%s from %s:%d%s\n",
+			" " x length $msg,
+			$header->[1], $header->[0],
+			$header->[1] eq $last->[1] ? ' <-- here' : '';
+	}
+
+	printf "%s:%d: warning: recursive header inclusion\n",
+		$first->[1], $first->[0];
+}
+
+# Find and print the smallest cycle starting in the specified node.
+sub detect_cycles {
+	my @queue = map { [[0, $_]] } @_;
+	while(@queue) {
+		my $top = pop @queue;
+		my $name = $top->[-1]->[1];
+
+		for my $dep (@{$deps{$name}}) {
+			my $chain = [@$top, [$dep->[0], $dep->[1]]];
+
+			# If the dep already exists in the chain, we have a
+			# cycle...
+			if(grep { $_->[1] eq $dep->[1] } @$top) {
+				print_cycle($chain);
+				next if $opt_all;
+				return;
+			}
+
+			push @queue, $chain;
+		}
+	}
+}
+
+sub mangle {
+	$_ = shift;
+	s/\//__/g;
+	s/\./_/g;
+	s/-/_/g;
+	$_;
+}
+
+# Output dependency graph in GraphViz language.
+sub graph {
+	print "digraph {\n";
+
+	print "\t/* vertices */\n";
+	for my $header (keys %deps) {
+		printf "\t%s [label=\"%s\"];\n",
+			mangle($header), $header;
+	}
+
+	print "\n";
+
+	print "\t/* edges */\n";
+	for my $header (keys %deps) {
+		for my $dep (@{$deps{$header}}) {
+			printf "\t%s -> %s;\n",
+				mangle($header), mangle($dep->[1]);
+		}
+	}
+
+	print "}\n";
+}