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, 57 insertions, 0 deletions

diff --git a/arch/powerpc/boot/redboot.h b/arch/powerpc/boot/redboot.h
new file mode 100644
index 000000000..8f319b1ad
--- /dev/null
+++ b/arch/powerpc/boot/redboot.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _PPC_REDBOOT_H
+#define _PPC_REDBOOT_H
+
+//=========================================================================
+// include/asm-ppc/redboot.h
+//   Copyright (c) 2002, 2003 Gary Thomas (<gary@mlbassoc.com>
+//   Copyright (c) 1997 Dan Malek (dmalek@jlc.net)
+
+//
+// Board specific details, as provided by RedBoot
+//
+
+/* A Board Information structure that is given to a program when
+ * RedBoot starts it up.  Note: not all fields make sense for all
+ * architectures and it's up to the platform specific code to fill
+ * in the details.
+ */
+typedef struct bd_info {
+    unsigned int   bi_tag;        /* Should be 0x42444944 "BDID" */
+    unsigned int   bi_size;       /* Size of this structure */
+    unsigned int   bi_revision;   /* revision of this structure */
+    unsigned int   bi_bdate;      /* bootstrap date, i.e. 0x19971106 */
+    unsigned int   bi_memstart;   /* Memory start address */
+    unsigned int   bi_memsize;    /* Memory (end) size in bytes */
+    unsigned int   bi_intfreq;    /* Internal Freq, in Hz */
+    unsigned int   bi_busfreq;    /* Bus Freq, in Hz */
+    unsigned int   bi_cpmfreq;    /* CPM Freq, in Hz */
+    unsigned int   bi_brgfreq;    /* BRG Freq, in Hz */
+    unsigned int   bi_vco;        /* VCO Out from PLL */
+    unsigned int   bi_pci_freq;   /* PCI Freq, in Hz */
+    unsigned int   bi_baudrate;   /* Default console baud rate */
+    unsigned int   bi_immr;       /* IMMR when called from boot rom */
+    unsigned char  bi_enetaddr[6];
+    unsigned int   bi_flashbase;  /* Physical address of FLASH memory */
+    unsigned int   bi_flashsize;  /* Length of FLASH memory */
+    int            bi_flashwidth; /* Width (8,16,32,64) */
+    unsigned char *bi_cmdline;    /* Pointer to command line */
+    unsigned char  bi_esa[3][6];  /* Ethernet station addresses */
+    unsigned int   bi_ramdisk_begin, bi_ramdisk_end;
+    struct {                      /* Information about [main] video screen */
+        short x_res;              /*   Horizontal resolution in pixels */
+        short y_res;              /*   Vertical resolution in pixels */
+        short bpp;                /*   Bits/pixel */
+        short mode;               /*   Type of pixels (packed, indexed) */
+        unsigned long fb;         /*   Pointer to frame buffer (pixel) memory */
+    } bi_video;
+    void         (*bi_cputc)(char);   /* Write a character to the RedBoot console */
+    char         (*bi_cgetc)(void);   /* Read a character from the RedBoot console */
+    int          (*bi_ctstc)(void);   /* Test for input on the RedBoot console */
+} bd_t;
+
+#define BI_REV 0x0102    /* Version 1.02 */
+
+#define bi_pci_busfreq bi_pci_freq
+#define bi_immr_base   bi_immr
+#endif