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, 176 insertions, 0 deletions

diff --git a/drivers/leds/trigger/ledtrig-cpu.c b/drivers/leds/trigger/ledtrig-cpu.c
new file mode 100644
index 000000000..679323c2c
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-cpu.c
@@ -0,0 +1,176 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ledtrig-cpu.c - LED trigger based on CPU activity
+ *
+ * This LED trigger will be registered for first 8 CPUs and named
+ * as cpu0..cpu7. There's additional trigger called cpu that
+ * is on when any CPU is active.
+ *
+ * If you want support for arbitrary number of CPUs, make it one trigger,
+ * with additional sysfs file selecting which CPU to watch.
+ *
+ * It can be bound to any LED just like other triggers using either a
+ * board file or via sysfs interface.
+ *
+ * An API named ledtrig_cpu is exported for any user, who want to add CPU
+ * activity indication in their code.
+ *
+ * Copyright 2011 Linus Walleij <linus.walleij@linaro.org>
+ * Copyright 2011 - 2012 Bryan Wu <bryan.wu@canonical.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/percpu.h>
+#include <linux/syscore_ops.h>
+#include <linux/rwsem.h>
+#include <linux/cpu.h>
+#include "../leds.h"
+
+#define MAX_NAME_LEN	8
+
+struct led_trigger_cpu {
+	bool is_active;
+	char name[MAX_NAME_LEN];
+	struct led_trigger *_trig;
+};
+
+static DEFINE_PER_CPU(struct led_trigger_cpu, cpu_trig);
+
+static struct led_trigger *trig_cpu_all;
+static atomic_t num_active_cpus = ATOMIC_INIT(0);
+
+/**
+ * ledtrig_cpu - emit a CPU event as a trigger
+ * @ledevt: CPU event to be emitted
+ *
+ * Emit a CPU event on a CPU core, which will trigger a
+ * bound LED to turn on or turn off.
+ */
+void ledtrig_cpu(enum cpu_led_event ledevt)
+{
+	struct led_trigger_cpu *trig = this_cpu_ptr(&cpu_trig);
+	bool is_active = trig->is_active;
+
+	/* Locate the correct CPU LED */
+	switch (ledevt) {
+	case CPU_LED_IDLE_END:
+	case CPU_LED_START:
+		/* Will turn the LED on, max brightness */
+		is_active = true;
+		break;
+
+	case CPU_LED_IDLE_START:
+	case CPU_LED_STOP:
+	case CPU_LED_HALTED:
+		/* Will turn the LED off */
+		is_active = false;
+		break;
+
+	default:
+		/* Will leave the LED as it is */
+		break;
+	}
+
+	if (is_active != trig->is_active) {
+		unsigned int active_cpus;
+		unsigned int total_cpus;
+
+		/* Update trigger state */
+		trig->is_active = is_active;
+		atomic_add(is_active ? 1 : -1, &num_active_cpus);
+		active_cpus = atomic_read(&num_active_cpus);
+		total_cpus = num_present_cpus();
+
+		led_trigger_event(trig->_trig,
+			is_active ? LED_FULL : LED_OFF);
+
+
+		led_trigger_event(trig_cpu_all,
+			DIV_ROUND_UP(LED_FULL * active_cpus, total_cpus));
+
+	}
+}
+EXPORT_SYMBOL(ledtrig_cpu);
+
+static int ledtrig_cpu_syscore_suspend(void *data)
+{
+	ledtrig_cpu(CPU_LED_STOP);
+	return 0;
+}
+
+static void ledtrig_cpu_syscore_resume(void *data)
+{
+	ledtrig_cpu(CPU_LED_START);
+}
+
+static void ledtrig_cpu_syscore_shutdown(void *data)
+{
+	ledtrig_cpu(CPU_LED_HALTED);
+}
+
+static const struct syscore_ops ledtrig_cpu_syscore_ops = {
+	.shutdown	= ledtrig_cpu_syscore_shutdown,
+	.suspend	= ledtrig_cpu_syscore_suspend,
+	.resume		= ledtrig_cpu_syscore_resume,
+};
+
+static struct syscore ledtrig_cpu_syscore = {
+	.ops = &ledtrig_cpu_syscore_ops,
+};
+
+static int ledtrig_online_cpu(unsigned int cpu)
+{
+	ledtrig_cpu(CPU_LED_START);
+	return 0;
+}
+
+static int ledtrig_prepare_down_cpu(unsigned int cpu)
+{
+	ledtrig_cpu(CPU_LED_STOP);
+	return 0;
+}
+
+static int __init ledtrig_cpu_init(void)
+{
+	unsigned int cpu;
+	int ret;
+
+	/* Supports up to 9999 cpu cores */
+	BUILD_BUG_ON(CONFIG_NR_CPUS > 9999);
+
+	/*
+	 * Registering a trigger for all CPUs.
+	 */
+	led_trigger_register_simple("cpu", &trig_cpu_all);
+
+	/*
+	 * Registering CPU led trigger for each CPU core here
+	 * ignores CPU hotplug, but after this CPU hotplug works
+	 * fine with this trigger.
+	 */
+	for_each_possible_cpu(cpu) {
+		struct led_trigger_cpu *trig = &per_cpu(cpu_trig, cpu);
+
+		if (cpu >= 8)
+			continue;
+
+		snprintf(trig->name, MAX_NAME_LEN, "cpu%u", cpu);
+
+		led_trigger_register_simple(trig->name, &trig->_trig);
+	}
+
+	register_syscore(&ledtrig_cpu_syscore);
+
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "leds/trigger:starting",
+				ledtrig_online_cpu, ledtrig_prepare_down_cpu);
+	if (ret < 0)
+		pr_err("CPU hotplug notifier for ledtrig-cpu could not be registered: %d\n",
+		       ret);
+
+	pr_info("ledtrig-cpu: registered to indicate activity on CPUs\n");
+
+	return 0;
+}
+device_initcall(ledtrig_cpu_init);