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, 73 insertions, 0 deletions

diff --git a/include/clocksource/timer-xilinx.h b/include/clocksource/timer-xilinx.h
new file mode 100644
index 000000000..d116f18de
--- /dev/null
+++ b/include/clocksource/timer-xilinx.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2021 Sean Anderson <sean.anderson@seco.com>
+ */
+
+#ifndef XILINX_TIMER_H
+#define XILINX_TIMER_H
+
+#include <linux/compiler.h>
+
+#define TCSR0	0x00
+#define TLR0	0x04
+#define TCR0	0x08
+#define TCSR1	0x10
+#define TLR1	0x14
+#define TCR1	0x18
+
+#define TCSR_MDT	BIT(0)
+#define TCSR_UDT	BIT(1)
+#define TCSR_GENT	BIT(2)
+#define TCSR_CAPT	BIT(3)
+#define TCSR_ARHT	BIT(4)
+#define TCSR_LOAD	BIT(5)
+#define TCSR_ENIT	BIT(6)
+#define TCSR_ENT	BIT(7)
+#define TCSR_TINT	BIT(8)
+#define TCSR_PWMA	BIT(9)
+#define TCSR_ENALL	BIT(10)
+#define TCSR_CASC	BIT(11)
+
+struct clk;
+struct device_node;
+struct regmap;
+
+/**
+ * struct xilinx_timer_priv - Private data for Xilinx AXI timer drivers
+ * @map: Regmap of the device, possibly with an offset
+ * @clk: Parent clock
+ * @max: Maximum value of the counters
+ */
+struct xilinx_timer_priv {
+	struct regmap *map;
+	struct clk *clk;
+	u64 max;
+};
+
+/**
+ * xilinx_timer_tlr_cycles() - Calculate the TLR for a period specified
+ *                             in clock cycles
+ * @priv: The timer's private data
+ * @tcsr: The value of the TCSR register for this counter
+ * @cycles: The number of cycles in this period
+ *
+ * Callers of this function MUST ensure that @cycles is representable as
+ * a TLR.
+ *
+ * Return: The calculated value for TLR
+ */
+u32 xilinx_timer_tlr_cycles(struct xilinx_timer_priv *priv, u32 tcsr,
+			    u64 cycles);
+
+/**
+ * xilinx_timer_get_period() - Get the current period of a counter
+ * @priv: The timer's private data
+ * @tlr: The value of TLR for this counter
+ * @tcsr: The value of TCSR for this counter
+ *
+ * Return: The period, in ns
+ */
+unsigned int xilinx_timer_get_period(struct xilinx_timer_priv *priv,
+				     u32 tlr, u32 tcsr);
+
+#endif /* XILINX_TIMER_H */