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, 47 insertions, 0 deletions

diff --git a/drivers/interconnect/internal.h b/drivers/interconnect/internal.h
new file mode 100644
index 000000000..3b9d50589
--- /dev/null
+++ b/drivers/interconnect/internal.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Interconnect framework internal structs
+ *
+ * Copyright (c) 2019, Linaro Ltd.
+ * Author: Georgi Djakov <georgi.djakov@linaro.org>
+ */
+
+#ifndef __DRIVERS_INTERCONNECT_INTERNAL_H
+#define __DRIVERS_INTERCONNECT_INTERNAL_H
+
+/**
+ * struct icc_req - constraints that are attached to each node
+ * @req_node: entry in list of requests for the particular @node
+ * @node: the interconnect node to which this constraint applies
+ * @dev: reference to the device that sets the constraints
+ * @enabled: indicates whether the path with this request is enabled
+ * @tag: path tag (optional)
+ * @avg_bw: an integer describing the average bandwidth in kBps
+ * @peak_bw: an integer describing the peak bandwidth in kBps
+ */
+struct icc_req {
+	struct hlist_node req_node;
+	struct icc_node *node;
+	struct device *dev;
+	bool enabled;
+	u32 tag;
+	u32 avg_bw;
+	u32 peak_bw;
+};
+
+/**
+ * struct icc_path - interconnect path structure
+ * @name: a string name of the path (useful for ftrace)
+ * @num_nodes: number of hops (nodes)
+ * @reqs: array of the requests applicable to this path of nodes
+ */
+struct icc_path {
+	const char *name;
+	size_t num_nodes;
+	struct icc_req reqs[] __counted_by(num_nodes);
+};
+
+struct icc_path *icc_get(struct device *dev, const char *src, const char *dst);
+int icc_debugfs_client_init(struct dentry *icc_dir);
+
+#endif