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, 281 insertions, 0 deletions

diff --git a/drivers/opp/debugfs.c b/drivers/opp/debugfs.c
new file mode 100644
index 000000000..61506d30d
--- /dev/null
+++ b/drivers/opp/debugfs.c
@@ -0,0 +1,281 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic OPP debugfs interface
+ *
+ * Copyright (C) 2015-2016 Viresh Kumar <viresh.kumar@linaro.org>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/init.h>
+#include <linux/limits.h>
+#include <linux/slab.h>
+
+#include "opp.h"
+
+static struct dentry *rootdir;
+
+static void opp_set_dev_name(const struct device *dev, char *name)
+{
+	if (dev->parent)
+		snprintf(name, NAME_MAX, "%s-%s", dev_name(dev->parent),
+			 dev_name(dev));
+	else
+		snprintf(name, NAME_MAX, "%s", dev_name(dev));
+}
+
+void opp_debug_remove_one(struct dev_pm_opp *opp)
+{
+	debugfs_remove_recursive(opp->dentry);
+}
+
+static ssize_t bw_name_read(struct file *fp, char __user *userbuf,
+			    size_t count, loff_t *ppos)
+{
+	struct icc_path *path = fp->private_data;
+	const char *name = icc_get_name(path);
+	char buf[64];
+	int i = 0;
+
+	if (name)
+		i = scnprintf(buf, sizeof(buf), "%.62s\n", name);
+
+	return simple_read_from_buffer(userbuf, count, ppos, buf, i);
+}
+
+static const struct file_operations bw_name_fops = {
+	.open = simple_open,
+	.read = bw_name_read,
+	.llseek = default_llseek,
+};
+
+static void opp_debug_create_bw(struct dev_pm_opp *opp,
+				struct opp_table *opp_table,
+				struct dentry *pdentry)
+{
+	struct dentry *d;
+	char name[] = "icc-path-XXXXXXXXXXX"; /* Integers can take 11 chars max */
+	int i;
+
+	for (i = 0; i < opp_table->path_count; i++) {
+		snprintf(name, sizeof(name), "icc-path-%d", i);
+
+		/* Create per-path directory */
+		d = debugfs_create_dir(name, pdentry);
+
+		debugfs_create_file("name", S_IRUGO, d, opp_table->paths[i],
+				    &bw_name_fops);
+		debugfs_create_u32("peak_bw", S_IRUGO, d,
+				   &opp->bandwidth[i].peak);
+		debugfs_create_u32("avg_bw", S_IRUGO, d,
+				   &opp->bandwidth[i].avg);
+	}
+}
+
+static void opp_debug_create_clks(struct dev_pm_opp *opp,
+				  struct opp_table *opp_table,
+				  struct dentry *pdentry)
+{
+	char name[] = "rate_hz_XXXXXXXXXXX"; /* Integers can take 11 chars max */
+	int i;
+
+	if (opp_table->clk_count == 1) {
+		debugfs_create_ulong("rate_hz", S_IRUGO, pdentry, &opp->rates[0]);
+		return;
+	}
+
+	for (i = 0; i < opp_table->clk_count; i++) {
+		snprintf(name, sizeof(name), "rate_hz_%d", i);
+		debugfs_create_ulong(name, S_IRUGO, pdentry, &opp->rates[i]);
+	}
+}
+
+static void opp_debug_create_supplies(struct dev_pm_opp *opp,
+				      struct opp_table *opp_table,
+				      struct dentry *pdentry)
+{
+	struct dentry *d;
+	int i;
+
+	for (i = 0; i < opp_table->regulator_count; i++) {
+		char name[] = "supply-XXXXXXXXXXX"; /* Integers can take 11 chars max */
+
+		snprintf(name, sizeof(name), "supply-%d", i);
+
+		/* Create per-opp directory */
+		d = debugfs_create_dir(name, pdentry);
+
+		debugfs_create_ulong("u_volt_target", S_IRUGO, d,
+				     &opp->supplies[i].u_volt);
+
+		debugfs_create_ulong("u_volt_min", S_IRUGO, d,
+				     &opp->supplies[i].u_volt_min);
+
+		debugfs_create_ulong("u_volt_max", S_IRUGO, d,
+				     &opp->supplies[i].u_volt_max);
+
+		debugfs_create_ulong("u_amp", S_IRUGO, d,
+				     &opp->supplies[i].u_amp);
+
+		debugfs_create_ulong("u_watt", S_IRUGO, d,
+				     &opp->supplies[i].u_watt);
+	}
+}
+
+void opp_debug_create_one(struct dev_pm_opp *opp, struct opp_table *opp_table)
+{
+	struct dentry *pdentry = opp_table->dentry;
+	struct dentry *d;
+	char name[36];	/* "opp:"(4) + u64(20) + "-" (1) + u32(10) + NULL(1) */
+
+	/*
+	 * Get directory name for OPP.
+	 *
+	 * - Normally rate is unique to each OPP, use it to get unique opp-name,
+	 *   together with performance level if available.
+	 * - For some devices rate isn't available or there are multiple, use
+	 *   index instead for them.
+	 */
+	if (likely(opp_table->clk_count == 1 && opp->rates[0])) {
+		if (opp->level == OPP_LEVEL_UNSET)
+			snprintf(name, sizeof(name), "opp:%lu", opp->rates[0]);
+		else
+			snprintf(name, sizeof(name), "opp:%lu-%u", opp->rates[0], opp->level);
+	} else {
+		snprintf(name, sizeof(name), "opp:%u", _get_opp_count(opp_table));
+	}
+
+	/* Create per-opp directory */
+	d = debugfs_create_dir(name, pdentry);
+
+	debugfs_create_bool("available", S_IRUGO, d, &opp->available);
+	debugfs_create_bool("dynamic", S_IRUGO, d, &opp->dynamic);
+	debugfs_create_bool("turbo", S_IRUGO, d, &opp->turbo);
+	debugfs_create_bool("suspend", S_IRUGO, d, &opp->suspend);
+	debugfs_create_u32("level", S_IRUGO, d, &opp->level);
+	debugfs_create_ulong("clock_latency_ns", S_IRUGO, d,
+			     &opp->clock_latency_ns);
+
+	opp->of_name = of_node_full_name(opp->np);
+	debugfs_create_str("of_name", S_IRUGO, d, (char **)&opp->of_name);
+
+	opp_debug_create_clks(opp, opp_table, d);
+	opp_debug_create_supplies(opp, opp_table, d);
+	opp_debug_create_bw(opp, opp_table, d);
+
+	opp->dentry = d;
+}
+
+static void opp_list_debug_create_dir(struct opp_device *opp_dev,
+				      struct opp_table *opp_table)
+{
+	const struct device *dev = opp_dev->dev;
+	struct dentry *d;
+
+	opp_set_dev_name(dev, opp_table->dentry_name);
+
+	/* Create device specific directory */
+	d = debugfs_create_dir(opp_table->dentry_name, rootdir);
+
+	opp_dev->dentry = d;
+	opp_table->dentry = d;
+}
+
+static void opp_list_debug_create_link(struct opp_device *opp_dev,
+				       struct opp_table *opp_table)
+{
+	char name[NAME_MAX];
+
+	opp_set_dev_name(opp_dev->dev, name);
+
+	/* Create device specific directory link */
+	opp_dev->dentry = debugfs_create_symlink(name, rootdir,
+						 opp_table->dentry_name);
+}
+
+/**
+ * opp_debug_register - add a device opp node to the debugfs 'opp' directory
+ * @opp_dev: opp-dev pointer for device
+ * @opp_table: the device-opp being added
+ *
+ * Dynamically adds device specific directory in debugfs 'opp' directory. If the
+ * device-opp is shared with other devices, then links will be created for all
+ * devices except the first.
+ */
+void opp_debug_register(struct opp_device *opp_dev, struct opp_table *opp_table)
+{
+	if (opp_table->dentry)
+		opp_list_debug_create_link(opp_dev, opp_table);
+	else
+		opp_list_debug_create_dir(opp_dev, opp_table);
+}
+
+static void opp_migrate_dentry(struct opp_device *opp_dev,
+			       struct opp_table *opp_table)
+{
+	struct opp_device *new_dev = NULL, *iter;
+	const struct device *dev;
+	int err;
+
+	/* Look for next opp-dev */
+	list_for_each_entry(iter, &opp_table->dev_list, node)
+		if (iter != opp_dev) {
+			new_dev = iter;
+			break;
+		}
+
+	BUG_ON(!new_dev);
+
+	/* new_dev is guaranteed to be valid here */
+	dev = new_dev->dev;
+	debugfs_remove_recursive(new_dev->dentry);
+
+	opp_set_dev_name(dev, opp_table->dentry_name);
+
+	err = debugfs_change_name(opp_dev->dentry, "%s", opp_table->dentry_name);
+	if (err) {
+		dev_err(dev, "%s: Failed to rename link from: %s to %s\n",
+			__func__, dev_name(opp_dev->dev), dev_name(dev));
+		return;
+	}
+
+	new_dev->dentry = opp_table->dentry = opp_dev->dentry;
+}
+
+/**
+ * opp_debug_unregister - remove a device opp node from debugfs opp directory
+ * @opp_dev: opp-dev pointer for device
+ * @opp_table: the device-opp being removed
+ *
+ * Dynamically removes device specific directory from debugfs 'opp' directory.
+ */
+void opp_debug_unregister(struct opp_device *opp_dev,
+			  struct opp_table *opp_table)
+{
+	if (opp_dev->dentry == opp_table->dentry) {
+		/* Move the real dentry object under another device */
+		if (!list_is_singular(&opp_table->dev_list)) {
+			opp_migrate_dentry(opp_dev, opp_table);
+			goto out;
+		}
+		opp_table->dentry = NULL;
+	}
+
+	debugfs_remove_recursive(opp_dev->dentry);
+
+out:
+	opp_dev->dentry = NULL;
+}
+
+static int __init opp_debug_init(void)
+{
+	/* Create /sys/kernel/debug/opp directory */
+	rootdir = debugfs_create_dir("opp", NULL);
+
+	return 0;
+}
+core_initcall(opp_debug_init);