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, 63 insertions, 0 deletions

diff --git a/drivers/cdx/controller/mcdid.h b/drivers/cdx/controller/mcdid.h
new file mode 100644
index 000000000..7fc29f099
--- /dev/null
+++ b/drivers/cdx/controller/mcdid.h
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright 2008-2013 Solarflare Communications Inc.
+ * Copyright (C) 2022-2025, Advanced Micro Devices, Inc.
+ */
+
+#ifndef CDX_MCDID_H
+#define CDX_MCDID_H
+
+#include <linux/mutex.h>
+#include <linux/kref.h>
+#include <linux/rpmsg.h>
+
+#include "mc_cdx_pcol.h"
+
+#ifdef DEBUG
+#define CDX_WARN_ON_ONCE_PARANOID(x) WARN_ON_ONCE(x)
+#define CDX_WARN_ON_PARANOID(x) WARN_ON(x)
+#else
+#define CDX_WARN_ON_ONCE_PARANOID(x) do {} while (0)
+#define CDX_WARN_ON_PARANOID(x) do {} while (0)
+#endif
+
+#define MCDI_BUF_LEN (8 + MCDI_CTL_SDU_LEN_MAX)
+
+static inline struct cdx_mcdi_iface *cdx_mcdi_if(struct cdx_mcdi *cdx)
+{
+	return cdx->mcdi ? &cdx->mcdi->iface : NULL;
+}
+
+int cdx_mcdi_rpc_async(struct cdx_mcdi *cdx, unsigned int cmd,
+		       const struct cdx_dword *inbuf, size_t inlen,
+		       cdx_mcdi_async_completer *complete,
+		       unsigned long cookie);
+int cdx_mcdi_wait_for_quiescence(struct cdx_mcdi *cdx,
+				 unsigned int timeout_jiffies);
+
+/*
+ * We expect that 16- and 32-bit fields in MCDI requests and responses
+ * are appropriately aligned, but 64-bit fields are only
+ * 32-bit-aligned.
+ */
+#define MCDI_BYTE(_buf, _field)						\
+	((void)BUILD_BUG_ON_ZERO(MC_CMD_ ## _field ## _LEN != 1),	\
+	 *MCDI_PTR(_buf, _field))
+#define MCDI_WORD(_buf, _field)						\
+	((void)BUILD_BUG_ON_ZERO(MC_CMD_ ## _field ## _LEN != 2),	\
+	 le16_to_cpu(*(__force const __le16 *)MCDI_PTR(_buf, _field)))
+#define MCDI_POPULATE_DWORD_1(_buf, _field, _name1, _value1)		\
+	CDX_POPULATE_DWORD_1(*_MCDI_DWORD(_buf, _field),		\
+			     MC_CMD_ ## _name1, _value1)
+#define MCDI_SET_QWORD(_buf, _field, _value)				\
+	do {								\
+		CDX_POPULATE_DWORD_1(_MCDI_DWORD(_buf, _field)[0],	\
+				     CDX_DWORD, (u32)(_value));	\
+		CDX_POPULATE_DWORD_1(_MCDI_DWORD(_buf, _field)[1],	\
+				     CDX_DWORD, (u64)(_value) >> 32);	\
+	} while (0)
+#define MCDI_QWORD(_buf, _field)					\
+	(CDX_DWORD_FIELD(_MCDI_DWORD(_buf, _field)[0], CDX_DWORD) |	\
+	(u64)CDX_DWORD_FIELD(_MCDI_DWORD(_buf, _field)[1], CDX_DWORD) << 32)
+
+#endif /* CDX_MCDID_H */