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, 139 insertions, 0 deletions

diff --git a/arch/powerpc/boot/ps3.c b/arch/powerpc/boot/ps3.c
new file mode 100644
index 000000000..89ff46b8b
--- /dev/null
+++ b/arch/powerpc/boot/ps3.c
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  PS3 bootwrapper support.
+ *
+ *  Copyright (C) 2007 Sony Computer Entertainment Inc.
+ *  Copyright 2007 Sony Corp.
+ */
+
+#include <stdarg.h>
+#include <stddef.h>
+#include "types.h"
+#include "elf.h"
+#include "string.h"
+#include "stdio.h"
+#include "page.h"
+#include "ops.h"
+
+extern int lv1_panic(u64 in_1);
+extern int lv1_get_logical_partition_id(u64 *out_1);
+extern int lv1_get_logical_ppe_id(u64 *out_1);
+extern int lv1_get_repository_node_value(u64 in_1, u64 in_2, u64 in_3,
+	u64 in_4, u64 in_5, u64 *out_1, u64 *out_2);
+
+BSS_STACK(4096);
+
+/* A buffer that may be edited by tools operating on a zImage binary so as to
+ * edit the command line passed to vmlinux (by setting /chosen/bootargs).
+ * The buffer is put in its own section so that tools may locate it easier.
+ */
+
+static char cmdline[BOOT_COMMAND_LINE_SIZE]
+	__attribute__((__section__("__builtin_cmdline")));
+
+static void prep_cmdline(void *chosen)
+{
+	if (cmdline[0] == '\0')
+		getprop(chosen, "bootargs", cmdline, BOOT_COMMAND_LINE_SIZE-1);
+	else
+		setprop_str(chosen, "bootargs", cmdline);
+
+	printf("cmdline: '%s'\n", cmdline);
+}
+
+static void ps3_console_write(const char *buf, int len)
+{
+}
+
+static void ps3_exit(void)
+{
+	printf("ps3_exit\n");
+
+	/* lv1_panic will shutdown the lpar. */
+
+	lv1_panic(0); /* zero = do not reboot */
+	while (1);
+}
+
+static int ps3_repository_read_rm_size(u64 *rm_size)
+{
+	int result;
+	u64 lpar_id;
+	u64 ppe_id;
+	u64 v2;
+
+	result = lv1_get_logical_partition_id(&lpar_id);
+
+	if (result)
+		return -1;
+
+	result = lv1_get_logical_ppe_id(&ppe_id);
+
+	if (result)
+		return -1;
+
+	/*
+	 * n1: 0000000062690000 : ....bi..
+	 * n2: 7075000000000000 : pu......
+	 * n3: 0000000000000001 : ........
+	 * n4: 726d5f73697a6500 : rm_size.
+	*/
+
+	result = lv1_get_repository_node_value(lpar_id, 0x0000000062690000ULL,
+		0x7075000000000000ULL, ppe_id, 0x726d5f73697a6500ULL, rm_size,
+		&v2);
+
+	printf("%s:%d: ppe_id  %lu \n", __func__, __LINE__,
+		(unsigned long)ppe_id);
+	printf("%s:%d: lpar_id %lu \n", __func__, __LINE__,
+		(unsigned long)lpar_id);
+	printf("%s:%d: rm_size %llxh \n", __func__, __LINE__, *rm_size);
+
+	return result ? -1 : 0;
+}
+
+void ps3_copy_vectors(void)
+{
+	extern char __system_reset_kernel[];
+
+	memcpy((void *)0x100, __system_reset_kernel, 512);
+	flush_cache((void *)0x100, 512);
+}
+
+void platform_init(void)
+{
+	const u32 heapsize = 0x1000000 - (u32)_end; /* 16MiB */
+	void *chosen;
+	unsigned long ft_addr;
+	u64 rm_size;
+
+	console_ops.write = ps3_console_write;
+	platform_ops.exit = ps3_exit;
+
+	printf("\n-- PS3 bootwrapper --\n");
+
+	simple_alloc_init(_end, heapsize, 32, 64);
+	fdt_init(_dtb_start);
+
+	chosen = finddevice("/chosen");
+
+	ps3_repository_read_rm_size(&rm_size);
+	dt_fixup_memory(0, rm_size);
+
+	if (&_initrd_end > &_initrd_start) {
+		setprop_val(chosen, "linux,initrd-start", (u32)(_initrd_start));
+		setprop_val(chosen, "linux,initrd-end", (u32)(_initrd_end));
+	}
+
+	prep_cmdline(chosen);
+
+	ft_addr = dt_ops.finalize();
+
+	ps3_copy_vectors();
+
+	printf(" flat tree at 0x%lx\n\r", ft_addr);
+
+	((kernel_entry_t)0)(ft_addr, 0, NULL);
+
+	ps3_exit();
+}