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, 137 insertions, 0 deletions

diff --git a/drivers/clocksource/bcm2835_timer.c b/drivers/clocksource/bcm2835_timer.c
new file mode 100644
index 000000000..d7662301b
--- /dev/null
+++ b/drivers/clocksource/bcm2835_timer.c
@@ -0,0 +1,137 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2012 Simon Arlott
+ */
+
+#include <linux/bitops.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/interrupt.h>
+#include <linux/irqreturn.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/sched_clock.h>
+
+#include <asm/irq.h>
+
+#define REG_CONTROL	0x00
+#define REG_COUNTER_LO	0x04
+#define REG_COUNTER_HI	0x08
+#define REG_COMPARE(n)	(0x0c + (n) * 4)
+#define MAX_TIMER	3
+#define DEFAULT_TIMER	3
+
+struct bcm2835_timer {
+	void __iomem *control;
+	void __iomem *compare;
+	int match_mask;
+	struct clock_event_device evt;
+};
+
+static void __iomem *system_clock __read_mostly;
+
+static u64 notrace bcm2835_sched_read(void)
+{
+	return readl_relaxed(system_clock);
+}
+
+static int bcm2835_time_set_next_event(unsigned long event,
+	struct clock_event_device *evt_dev)
+{
+	struct bcm2835_timer *timer = container_of(evt_dev,
+		struct bcm2835_timer, evt);
+	writel_relaxed(readl_relaxed(system_clock) + event,
+		timer->compare);
+	return 0;
+}
+
+static irqreturn_t bcm2835_time_interrupt(int irq, void *dev_id)
+{
+	struct bcm2835_timer *timer = dev_id;
+	void (*event_handler)(struct clock_event_device *);
+	if (readl_relaxed(timer->control) & timer->match_mask) {
+		writel_relaxed(timer->match_mask, timer->control);
+
+		event_handler = READ_ONCE(timer->evt.event_handler);
+		if (event_handler)
+			event_handler(&timer->evt);
+		return IRQ_HANDLED;
+	} else {
+		return IRQ_NONE;
+	}
+}
+
+static int __init bcm2835_timer_init(struct device_node *node)
+{
+	void __iomem *base;
+	u32 freq;
+	int irq, ret;
+	struct bcm2835_timer *timer;
+
+	base = of_iomap(node, 0);
+	if (!base) {
+		pr_err("Can't remap registers\n");
+		return -ENXIO;
+	}
+
+	ret = of_property_read_u32(node, "clock-frequency", &freq);
+	if (ret) {
+		pr_err("Can't read clock-frequency\n");
+		goto err_iounmap;
+	}
+
+	system_clock = base + REG_COUNTER_LO;
+	sched_clock_register(bcm2835_sched_read, 32, freq);
+
+	clocksource_mmio_init(base + REG_COUNTER_LO, node->name,
+		freq, 300, 32, clocksource_mmio_readl_up);
+
+	irq = irq_of_parse_and_map(node, DEFAULT_TIMER);
+	if (irq <= 0) {
+		pr_err("Can't parse IRQ\n");
+		ret = -EINVAL;
+		goto err_iounmap;
+	}
+
+	timer = kzalloc_obj(*timer);
+	if (!timer) {
+		ret = -ENOMEM;
+		goto err_iounmap;
+	}
+
+	timer->control = base + REG_CONTROL;
+	timer->compare = base + REG_COMPARE(DEFAULT_TIMER);
+	timer->match_mask = BIT(DEFAULT_TIMER);
+	timer->evt.name = node->name;
+	timer->evt.rating = 300;
+	timer->evt.features = CLOCK_EVT_FEAT_ONESHOT;
+	timer->evt.set_next_event = bcm2835_time_set_next_event;
+	timer->evt.cpumask = cpumask_of(0);
+
+	ret = request_irq(irq, bcm2835_time_interrupt, IRQF_TIMER | IRQF_SHARED,
+			  node->name, timer);
+	if (ret) {
+		pr_err("Can't set up timer IRQ\n");
+		goto err_timer_free;
+	}
+
+	clockevents_config_and_register(&timer->evt, freq, 0xf, 0xffffffff);
+
+	pr_info("bcm2835: system timer (irq = %d)\n", irq);
+
+	return 0;
+
+err_timer_free:
+	kfree(timer);
+
+err_iounmap:
+	iounmap(base);
+	return ret;
+}
+TIMER_OF_DECLARE(bcm2835, "brcm,bcm2835-system-timer",
+			bcm2835_timer_init);