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, 68 insertions, 0 deletions

diff --git a/drivers/extcon/extcon.h b/drivers/extcon/extcon.h
new file mode 100644
index 000000000..946182687
--- /dev/null
+++ b/drivers/extcon/extcon.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LINUX_EXTCON_INTERNAL_H__
+#define __LINUX_EXTCON_INTERNAL_H__
+
+#include <linux/extcon-provider.h>
+
+/**
+ * struct extcon_dev - An extcon device represents one external connector.
+ * @name:		The name of this extcon device. Parent device name is
+ *			used if NULL.
+ * @supported_cable:	Array of supported cable names ending with EXTCON_NONE.
+ *			If supported_cable is NULL, cable name related APIs
+ *			are disabled.
+ * @mutually_exclusive:	Array of mutually exclusive set of cables that cannot
+ *			be attached simultaneously. The array should be
+ *			ending with 0 or be NULL (no mutually exclusive cables).
+ *			For example, if it is {0x7, 0x30, 0}, then,
+ *			{0, 1}, {0, 1, 2}, {0, 2}, {1, 2}, or {4, 5} cannot
+ *			be attached simulataneously. {0x7, 0} is equivalent to
+ *			{0x3, 0x6, 0x5, 0}. If it is {0xFFFFFFFF, 0}, there
+ *			can be no simultaneous connections.
+ * @dev:		Device of this extcon.
+ * @id:			Unique device ID of this extcon.
+ * @state:		Attach/detach state of this extcon. Do not provide at
+ *			register-time.
+ * @nh_all:		Notifier for the state change events for all supported
+ *			external connectors from this extcon.
+ * @nh:			Notifier for the state change events from this extcon
+ * @entry:		To support list of extcon devices so that users can
+ *			search for extcon devices based on the extcon name.
+ * @lock:		Protects device state and serialises device registration
+ * @max_supported:	Internal value to store the number of cables.
+ * @extcon_dev_type:	Device_type struct to provide attribute_groups
+ *			customized for each extcon device.
+ * @cables:		Sysfs subdirectories. Each represents one cable.
+ *
+ * In most cases, users only need to provide "User initializing data" of
+ * this struct when registering an extcon. In some exceptional cases,
+ * optional callbacks may be needed. However, the values in "internal data"
+ * are overwritten by register function.
+ */
+struct extcon_dev {
+	/* Optional user initializing data */
+	const char *name;
+	const unsigned int *supported_cable;
+	const u32 *mutually_exclusive;
+
+	/* Internal data. Please do not set. */
+	struct device dev;
+	unsigned int id;
+	struct raw_notifier_head nh_all;
+	struct raw_notifier_head *nh;
+	struct list_head entry;
+	int max_supported;
+	spinlock_t lock;	/* could be called by irq handler */
+	u32 state;
+
+	/* /sys/class/extcon/.../cable.n/... */
+	struct device_type extcon_dev_type;
+	struct extcon_cable *cables;
+
+	/* /sys/class/extcon/.../mutually_exclusive/... */
+	struct attribute_group attr_g_muex;
+	struct attribute **attrs_muex;
+	struct device_attribute *d_attrs_muex;
+};
+
+#endif /* __LINUX_EXTCON_INTERNAL_H__ */