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, 294 insertions, 0 deletions

diff --git a/lib/tests/base64_kunit.c b/lib/tests/base64_kunit.c
new file mode 100644
index 000000000..f7252070c
--- /dev/null
+++ b/lib/tests/base64_kunit.c
@@ -0,0 +1,294 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * base64_kunit_test.c - KUnit tests for base64 encoding and decoding functions
+ *
+ * Copyright (c) 2025, Guan-Chun Wu <409411716@gms.tku.edu.tw>
+ */
+
+#include <kunit/test.h>
+#include <linux/base64.h>
+
+/* ---------- Benchmark helpers ---------- */
+static u64 bench_encode_ns(const u8 *data, int len, char *dst, int reps,
+			   enum base64_variant variant)
+{
+	u64 t0, t1;
+
+	t0 = ktime_get_ns();
+	for (int i = 0; i < reps; i++)
+		base64_encode(data, len, dst, true, variant);
+	t1 = ktime_get_ns();
+
+	return div64_u64(t1 - t0, (u64)reps);
+}
+
+static u64 bench_decode_ns(const char *data, int len, u8 *dst, int reps,
+			   enum base64_variant variant)
+{
+	u64 t0, t1;
+
+	t0 = ktime_get_ns();
+	for (int i = 0; i < reps; i++)
+		base64_decode(data, len, dst, true, variant);
+	t1 = ktime_get_ns();
+
+	return div64_u64(t1 - t0, (u64)reps);
+}
+
+static void run_perf_and_check(struct kunit *test, const char *label, int size,
+			       enum base64_variant variant)
+{
+	const int reps = 1000;
+	size_t outlen = DIV_ROUND_UP(size, 3) * 4;
+	u8 *in = kmalloc(size, GFP_KERNEL);
+	char *enc = kmalloc(outlen, GFP_KERNEL);
+	u8 *decoded = kmalloc(size, GFP_KERNEL);
+
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, in);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, enc);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, decoded);
+
+	get_random_bytes(in, size);
+	int enc_len = base64_encode(in, size, enc, true, variant);
+	int dec_len = base64_decode(enc, enc_len, decoded, true, variant);
+
+	/* correctness sanity check */
+	KUNIT_EXPECT_EQ(test, dec_len, size);
+	KUNIT_EXPECT_MEMEQ(test, decoded, in, size);
+
+	/* benchmark encode */
+
+	u64 t1 = bench_encode_ns(in, size, enc, reps, variant);
+
+	kunit_info(test, "[%s] encode run : %lluns", label, t1);
+
+	u64 t2 = bench_decode_ns(enc, enc_len, decoded, reps, variant);
+
+	kunit_info(test, "[%s] decode run : %lluns", label, t2);
+
+	kfree(in);
+	kfree(enc);
+	kfree(decoded);
+}
+
+static void base64_performance_tests(struct kunit *test)
+{
+	/* run on STD variant only */
+	run_perf_and_check(test, "64B", 64, BASE64_STD);
+	run_perf_and_check(test, "1KB", 1024, BASE64_STD);
+}
+
+/* ---------- Helpers for encode ---------- */
+static void expect_encode_ok(struct kunit *test, const u8 *src, int srclen,
+			     const char *expected, bool padding,
+			     enum base64_variant variant)
+{
+	char buf[128];
+	int encoded_len = base64_encode(src, srclen, buf, padding, variant);
+
+	buf[encoded_len] = '\0';
+
+	KUNIT_EXPECT_EQ(test, encoded_len, strlen(expected));
+	KUNIT_EXPECT_STREQ(test, buf, expected);
+}
+
+/* ---------- Helpers for decode ---------- */
+static void expect_decode_ok(struct kunit *test, const char *src,
+			     const u8 *expected, int expected_len, bool padding,
+			     enum base64_variant variant)
+{
+	u8 buf[128];
+	int decoded_len = base64_decode(src, strlen(src), buf, padding, variant);
+
+	KUNIT_EXPECT_EQ(test, decoded_len, expected_len);
+	KUNIT_EXPECT_MEMEQ(test, buf, expected, expected_len);
+}
+
+static void expect_decode_err(struct kunit *test, const char *src,
+			      int srclen, bool padding,
+			      enum base64_variant variant)
+{
+	u8 buf[64];
+	int decoded_len = base64_decode(src, srclen, buf, padding, variant);
+
+	KUNIT_EXPECT_EQ(test, decoded_len, -1);
+}
+
+/* ---------- Encode Tests ---------- */
+static void base64_std_encode_tests(struct kunit *test)
+{
+	/* With padding */
+	expect_encode_ok(test, (const u8 *)"", 0, "", true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"f", 1, "Zg==", true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"fo", 2, "Zm8=", true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"foo", 3, "Zm9v", true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"foob", 4, "Zm9vYg==", true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"fooba", 5, "Zm9vYmE=", true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"foobar", 6, "Zm9vYmFy", true, BASE64_STD);
+
+	/* Extra cases with padding */
+	expect_encode_ok(test, (const u8 *)"Hello, world!", 13, "SGVsbG8sIHdvcmxkIQ==",
+			 true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"ABCDEFGHIJKLMNOPQRSTUVWXYZ", 26,
+			 "QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVo=", true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"abcdefghijklmnopqrstuvwxyz", 26,
+			 "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXo=", true, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"0123456789+/", 12, "MDEyMzQ1Njc4OSsv",
+			 true, BASE64_STD);
+
+	/* Without padding */
+	expect_encode_ok(test, (const u8 *)"", 0, "", false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"f", 1, "Zg", false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"fo", 2, "Zm8", false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"foo", 3, "Zm9v", false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"foob", 4, "Zm9vYg", false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"fooba", 5, "Zm9vYmE", false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"foobar", 6, "Zm9vYmFy", false, BASE64_STD);
+
+	/* Extra cases without padding */
+	expect_encode_ok(test, (const u8 *)"Hello, world!", 13, "SGVsbG8sIHdvcmxkIQ",
+			 false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"ABCDEFGHIJKLMNOPQRSTUVWXYZ", 26,
+			 "QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVo", false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"abcdefghijklmnopqrstuvwxyz", 26,
+			 "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXo", false, BASE64_STD);
+	expect_encode_ok(test, (const u8 *)"0123456789+/", 12, "MDEyMzQ1Njc4OSsv",
+			 false, BASE64_STD);
+}
+
+/* ---------- Decode Tests ---------- */
+static void base64_std_decode_tests(struct kunit *test)
+{
+	/* -------- With padding --------*/
+	expect_decode_ok(test, "", (const u8 *)"", 0, true, BASE64_STD);
+	expect_decode_ok(test, "Zg==", (const u8 *)"f", 1, true, BASE64_STD);
+	expect_decode_ok(test, "Zm8=", (const u8 *)"fo", 2, true, BASE64_STD);
+	expect_decode_ok(test, "Zm9v", (const u8 *)"foo", 3, true, BASE64_STD);
+	expect_decode_ok(test, "Zm9vYg==", (const u8 *)"foob", 4, true, BASE64_STD);
+	expect_decode_ok(test, "Zm9vYmE=", (const u8 *)"fooba", 5, true, BASE64_STD);
+	expect_decode_ok(test, "Zm9vYmFy", (const u8 *)"foobar", 6, true, BASE64_STD);
+	expect_decode_ok(test, "SGVsbG8sIHdvcmxkIQ==", (const u8 *)"Hello, world!", 13,
+			 true, BASE64_STD);
+	expect_decode_ok(test, "QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVo=",
+			 (const u8 *)"ABCDEFGHIJKLMNOPQRSTUVWXYZ", 26, true, BASE64_STD);
+	expect_decode_ok(test, "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXo=",
+			 (const u8 *)"abcdefghijklmnopqrstuvwxyz", 26, true, BASE64_STD);
+
+	/* Error cases */
+	expect_decode_err(test, "Zg=!", 4, true, BASE64_STD);
+	expect_decode_err(test, "Zm$=", 4, true, BASE64_STD);
+	expect_decode_err(test, "Z===", 4, true, BASE64_STD);
+	expect_decode_err(test, "Zg", 2, true, BASE64_STD);
+	expect_decode_err(test, "Zm9v====", 8, true, BASE64_STD);
+	expect_decode_err(test, "Zm==A", 5, true, BASE64_STD);
+
+	{
+		char with_nul[4] = { 'Z', 'g', '\0', '=' };
+
+		expect_decode_err(test, with_nul, 4, true, BASE64_STD);
+	}
+
+	/* -------- Without padding --------*/
+	expect_decode_ok(test, "", (const u8 *)"", 0, false, BASE64_STD);
+	expect_decode_ok(test, "Zg", (const u8 *)"f", 1, false, BASE64_STD);
+	expect_decode_ok(test, "Zm8", (const u8 *)"fo", 2, false, BASE64_STD);
+	expect_decode_ok(test, "Zm9v", (const u8 *)"foo", 3, false, BASE64_STD);
+	expect_decode_ok(test, "Zm9vYg", (const u8 *)"foob", 4, false, BASE64_STD);
+	expect_decode_ok(test, "Zm9vYmE", (const u8 *)"fooba", 5, false, BASE64_STD);
+	expect_decode_ok(test, "Zm9vYmFy", (const u8 *)"foobar", 6, false, BASE64_STD);
+	expect_decode_ok(test, "TWFu", (const u8 *)"Man", 3, false, BASE64_STD);
+	expect_decode_ok(test, "SGVsbG8sIHdvcmxkIQ", (const u8 *)"Hello, world!", 13,
+			 false, BASE64_STD);
+	expect_decode_ok(test, "QUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVo",
+			 (const u8 *)"ABCDEFGHIJKLMNOPQRSTUVWXYZ", 26, false, BASE64_STD);
+	expect_decode_ok(test, "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXo",
+			 (const u8 *)"abcdefghijklmnopqrstuvwxyz", 26, false, BASE64_STD);
+	expect_decode_ok(test, "MDEyMzQ1Njc4OSsv", (const u8 *)"0123456789+/", 12,
+			 false, BASE64_STD);
+
+	/* Error cases */
+	expect_decode_err(test, "Zg=!", 4, false, BASE64_STD);
+	expect_decode_err(test, "Zm$=", 4, false, BASE64_STD);
+	expect_decode_err(test, "Z===", 4, false, BASE64_STD);
+	expect_decode_err(test, "Zg=", 3, false, BASE64_STD);
+	expect_decode_err(test, "Zm9v====", 8, false, BASE64_STD);
+	expect_decode_err(test, "Zm==v", 4, false, BASE64_STD);
+
+	{
+		char with_nul[4] = { 'Z', 'g', '\0', '=' };
+
+		expect_decode_err(test, with_nul, 4, false, BASE64_STD);
+	}
+}
+
+/* ---------- Variant tests (URLSAFE / IMAP) ---------- */
+static void base64_variant_tests(struct kunit *test)
+{
+	const u8 sample1[] = { 0x00, 0xfb, 0xff, 0x7f, 0x80 };
+	char std_buf[128], url_buf[128], imap_buf[128];
+	u8 back[128];
+	int n_std, n_url, n_imap, m;
+	int i;
+
+	n_std = base64_encode(sample1, sizeof(sample1), std_buf, false, BASE64_STD);
+	n_url = base64_encode(sample1, sizeof(sample1), url_buf, false, BASE64_URLSAFE);
+	std_buf[n_std] = '\0';
+	url_buf[n_url] = '\0';
+
+	for (i = 0; i < n_std; i++) {
+		if (std_buf[i] == '+')
+			std_buf[i] = '-';
+		else if (std_buf[i] == '/')
+			std_buf[i] = '_';
+	}
+	KUNIT_EXPECT_STREQ(test, std_buf, url_buf);
+
+	m = base64_decode(url_buf, n_url, back, false, BASE64_URLSAFE);
+	KUNIT_EXPECT_EQ(test, m, (int)sizeof(sample1));
+	KUNIT_EXPECT_MEMEQ(test, back, sample1, sizeof(sample1));
+
+	n_std  = base64_encode(sample1, sizeof(sample1), std_buf, false, BASE64_STD);
+	n_imap = base64_encode(sample1, sizeof(sample1), imap_buf, false, BASE64_IMAP);
+	std_buf[n_std]   = '\0';
+	imap_buf[n_imap] = '\0';
+
+	for (i = 0; i < n_std; i++)
+		if (std_buf[i] == '/')
+			std_buf[i] = ',';
+	KUNIT_EXPECT_STREQ(test, std_buf, imap_buf);
+
+	m = base64_decode(imap_buf, n_imap, back, false, BASE64_IMAP);
+	KUNIT_EXPECT_EQ(test, m, (int)sizeof(sample1));
+	KUNIT_EXPECT_MEMEQ(test, back, sample1, sizeof(sample1));
+
+	{
+		const char *bad = "Zg==";
+		u8 tmp[8];
+
+		m = base64_decode(bad, strlen(bad), tmp, false, BASE64_URLSAFE);
+		KUNIT_EXPECT_EQ(test, m, -1);
+
+		m = base64_decode(bad, strlen(bad), tmp, false, BASE64_IMAP);
+		KUNIT_EXPECT_EQ(test, m, -1);
+	}
+}
+
+/* ---------- Test registration ---------- */
+static struct kunit_case base64_test_cases[] = {
+	KUNIT_CASE(base64_performance_tests),
+	KUNIT_CASE(base64_std_encode_tests),
+	KUNIT_CASE(base64_std_decode_tests),
+	KUNIT_CASE(base64_variant_tests),
+	{}
+};
+
+static struct kunit_suite base64_test_suite = {
+	.name = "base64",
+	.test_cases = base64_test_cases,
+};
+
+kunit_test_suite(base64_test_suite);
+
+MODULE_AUTHOR("Guan-Chun Wu <409411716@gms.tku.edu.tw>");
+MODULE_DESCRIPTION("KUnit tests for Base64 encoding/decoding, including performance checks");
+MODULE_LICENSE("GPL");