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, 265 insertions, 0 deletions

diff --git a/drivers/firmware/dmi-id.c b/drivers/firmware/dmi-id.c
new file mode 100644
index 000000000..477a37e2e
--- /dev/null
+++ b/drivers/firmware/dmi-id.c
@@ -0,0 +1,265 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Export SMBIOS/DMI info via sysfs to userspace
+ *
+ * Copyright 2007, Lennart Poettering
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/dmi.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+
+struct dmi_device_attribute{
+	struct device_attribute dev_attr;
+	int field;
+};
+#define to_dmi_dev_attr(_dev_attr) \
+	container_of(_dev_attr, struct dmi_device_attribute, dev_attr)
+
+static ssize_t sys_dmi_field_show(struct device *dev,
+				  struct device_attribute *attr,
+				  char *page)
+{
+	int field = to_dmi_dev_attr(attr)->field;
+	ssize_t len;
+	len = scnprintf(page, PAGE_SIZE, "%s\n", dmi_get_system_info(field));
+	page[len-1] = '\n';
+	return len;
+}
+
+#define DMI_ATTR(_name, _mode, _show, _field)			\
+	{ .dev_attr = __ATTR(_name, _mode, _show, NULL),	\
+	  .field = _field }
+
+#define DEFINE_DMI_ATTR_WITH_SHOW(_name, _mode, _field)		\
+static struct dmi_device_attribute sys_dmi_##_name##_attr =	\
+	DMI_ATTR(_name, _mode, sys_dmi_field_show, _field);
+
+DEFINE_DMI_ATTR_WITH_SHOW(bios_vendor,		0444, DMI_BIOS_VENDOR);
+DEFINE_DMI_ATTR_WITH_SHOW(bios_version,		0444, DMI_BIOS_VERSION);
+DEFINE_DMI_ATTR_WITH_SHOW(bios_date,		0444, DMI_BIOS_DATE);
+DEFINE_DMI_ATTR_WITH_SHOW(sys_vendor,		0444, DMI_SYS_VENDOR);
+DEFINE_DMI_ATTR_WITH_SHOW(bios_release,		0444, DMI_BIOS_RELEASE);
+DEFINE_DMI_ATTR_WITH_SHOW(ec_firmware_release,	0444, DMI_EC_FIRMWARE_RELEASE);
+DEFINE_DMI_ATTR_WITH_SHOW(product_name,		0444, DMI_PRODUCT_NAME);
+DEFINE_DMI_ATTR_WITH_SHOW(product_version,	0444, DMI_PRODUCT_VERSION);
+DEFINE_DMI_ATTR_WITH_SHOW(product_serial,	0400, DMI_PRODUCT_SERIAL);
+DEFINE_DMI_ATTR_WITH_SHOW(product_uuid,		0400, DMI_PRODUCT_UUID);
+DEFINE_DMI_ATTR_WITH_SHOW(product_sku,		0444, DMI_PRODUCT_SKU);
+DEFINE_DMI_ATTR_WITH_SHOW(product_family,	0444, DMI_PRODUCT_FAMILY);
+DEFINE_DMI_ATTR_WITH_SHOW(board_vendor,		0444, DMI_BOARD_VENDOR);
+DEFINE_DMI_ATTR_WITH_SHOW(board_name,		0444, DMI_BOARD_NAME);
+DEFINE_DMI_ATTR_WITH_SHOW(board_version,	0444, DMI_BOARD_VERSION);
+DEFINE_DMI_ATTR_WITH_SHOW(board_serial,		0400, DMI_BOARD_SERIAL);
+DEFINE_DMI_ATTR_WITH_SHOW(board_asset_tag,	0444, DMI_BOARD_ASSET_TAG);
+DEFINE_DMI_ATTR_WITH_SHOW(chassis_vendor,	0444, DMI_CHASSIS_VENDOR);
+DEFINE_DMI_ATTR_WITH_SHOW(chassis_type,		0444, DMI_CHASSIS_TYPE);
+DEFINE_DMI_ATTR_WITH_SHOW(chassis_version,	0444, DMI_CHASSIS_VERSION);
+DEFINE_DMI_ATTR_WITH_SHOW(chassis_serial,	0400, DMI_CHASSIS_SERIAL);
+DEFINE_DMI_ATTR_WITH_SHOW(chassis_asset_tag,	0444, DMI_CHASSIS_ASSET_TAG);
+
+static void ascii_filter(char *d, const char *s)
+{
+	/* Filter out characters we don't want to see in the modalias string */
+	for (; *s; s++)
+		if (*s > ' ' && *s < 127 && *s != ':')
+			*(d++) = *s;
+
+	*d = 0;
+}
+
+static ssize_t get_modalias(char *buffer, size_t buffer_size)
+{
+	/*
+	 * Note new fields need to be added at the end to keep compatibility
+	 * with udev's hwdb which does matches on "`cat dmi/id/modalias`*".
+	 */
+	static const struct mafield {
+		const char *prefix;
+		int field;
+	} fields[] = {
+		{ "bvn", DMI_BIOS_VENDOR },
+		{ "bvr", DMI_BIOS_VERSION },
+		{ "bd",  DMI_BIOS_DATE },
+		{ "br",  DMI_BIOS_RELEASE },
+		{ "efr", DMI_EC_FIRMWARE_RELEASE },
+		{ "svn", DMI_SYS_VENDOR },
+		{ "pn",  DMI_PRODUCT_NAME },
+		{ "pvr", DMI_PRODUCT_VERSION },
+		{ "rvn", DMI_BOARD_VENDOR },
+		{ "rn",  DMI_BOARD_NAME },
+		{ "rvr", DMI_BOARD_VERSION },
+		{ "cvn", DMI_CHASSIS_VENDOR },
+		{ "ct",  DMI_CHASSIS_TYPE },
+		{ "cvr", DMI_CHASSIS_VERSION },
+		{ "sku", DMI_PRODUCT_SKU },
+		{ "pfa", DMI_PRODUCT_FAMILY },
+		{ NULL,  DMI_NONE }
+	};
+
+	ssize_t l, left;
+	char *p;
+	const struct mafield *f;
+
+	strcpy(buffer, "dmi");
+	p = buffer + 3; left = buffer_size - 4;
+
+	for (f = fields; f->prefix && left > 0; f++) {
+		const char *c;
+		char *t;
+
+		c = dmi_get_system_info(f->field);
+		if (!c)
+			continue;
+
+		t = kmalloc(strlen(c) + 1, GFP_KERNEL);
+		if (!t)
+			break;
+		ascii_filter(t, c);
+		l = scnprintf(p, left, ":%s%s", f->prefix, t);
+		kfree(t);
+
+		p += l;
+		left -= l;
+	}
+
+	p[0] = ':';
+	p[1] = 0;
+
+	return p - buffer + 1;
+}
+
+static ssize_t sys_dmi_modalias_show(struct device *dev,
+				     struct device_attribute *attr, char *page)
+{
+	ssize_t r;
+	r = get_modalias(page, PAGE_SIZE-1);
+	page[r] = '\n';
+	page[r+1] = 0;
+	return r+1;
+}
+
+static struct device_attribute sys_dmi_modalias_attr =
+	__ATTR(modalias, 0444, sys_dmi_modalias_show, NULL);
+
+static struct attribute *sys_dmi_attributes[DMI_STRING_MAX+2];
+
+static struct attribute_group sys_dmi_attribute_group = {
+	.attrs = sys_dmi_attributes,
+};
+
+static const struct attribute_group* sys_dmi_attribute_groups[] = {
+	&sys_dmi_attribute_group,
+	NULL
+};
+
+static int dmi_dev_uevent(const struct device *dev, struct kobj_uevent_env *env)
+{
+	ssize_t len;
+
+	if (add_uevent_var(env, "MODALIAS="))
+		return -ENOMEM;
+	len = get_modalias(&env->buf[env->buflen - 1],
+			   sizeof(env->buf) - env->buflen);
+	if (len >= (sizeof(env->buf) - env->buflen))
+		return -ENOMEM;
+	env->buflen += len;
+	return 0;
+}
+
+static void dmi_dev_release(struct device *dev)
+{
+	kfree(dev);
+}
+
+static struct class dmi_class = {
+	.name = "dmi",
+	.dev_release = dmi_dev_release,
+	.dev_uevent = dmi_dev_uevent,
+};
+
+static struct device *dmi_dev;
+
+/* Initialization */
+
+#define ADD_DMI_ATTR(_name, _field) \
+	if (dmi_get_system_info(_field)) \
+		sys_dmi_attributes[i++] = &sys_dmi_##_name##_attr.dev_attr.attr;
+
+/* In a separate function to keep gcc 3.2 happy - do NOT merge this in
+   dmi_id_init! */
+static void __init dmi_id_init_attr_table(void)
+{
+	int i;
+
+	/* Not necessarily all DMI fields are available on all
+	 * systems, hence let's built an attribute table of just
+	 * what's available */
+	i = 0;
+	ADD_DMI_ATTR(bios_vendor,       DMI_BIOS_VENDOR);
+	ADD_DMI_ATTR(bios_version,      DMI_BIOS_VERSION);
+	ADD_DMI_ATTR(bios_date,         DMI_BIOS_DATE);
+	ADD_DMI_ATTR(bios_release,      DMI_BIOS_RELEASE);
+	ADD_DMI_ATTR(ec_firmware_release, DMI_EC_FIRMWARE_RELEASE);
+	ADD_DMI_ATTR(sys_vendor,        DMI_SYS_VENDOR);
+	ADD_DMI_ATTR(product_name,      DMI_PRODUCT_NAME);
+	ADD_DMI_ATTR(product_version,   DMI_PRODUCT_VERSION);
+	ADD_DMI_ATTR(product_serial,    DMI_PRODUCT_SERIAL);
+	ADD_DMI_ATTR(product_uuid,      DMI_PRODUCT_UUID);
+	ADD_DMI_ATTR(product_family,    DMI_PRODUCT_FAMILY);
+	ADD_DMI_ATTR(product_sku,       DMI_PRODUCT_SKU);
+	ADD_DMI_ATTR(board_vendor,      DMI_BOARD_VENDOR);
+	ADD_DMI_ATTR(board_name,        DMI_BOARD_NAME);
+	ADD_DMI_ATTR(board_version,     DMI_BOARD_VERSION);
+	ADD_DMI_ATTR(board_serial,      DMI_BOARD_SERIAL);
+	ADD_DMI_ATTR(board_asset_tag,   DMI_BOARD_ASSET_TAG);
+	ADD_DMI_ATTR(chassis_vendor,    DMI_CHASSIS_VENDOR);
+	ADD_DMI_ATTR(chassis_type,      DMI_CHASSIS_TYPE);
+	ADD_DMI_ATTR(chassis_version,   DMI_CHASSIS_VERSION);
+	ADD_DMI_ATTR(chassis_serial,    DMI_CHASSIS_SERIAL);
+	ADD_DMI_ATTR(chassis_asset_tag, DMI_CHASSIS_ASSET_TAG);
+	sys_dmi_attributes[i++] = &sys_dmi_modalias_attr.attr;
+}
+
+static int __init dmi_id_init(void)
+{
+	int ret;
+
+	if (!dmi_available)
+		return -ENODEV;
+
+	dmi_id_init_attr_table();
+
+	ret = class_register(&dmi_class);
+	if (ret)
+		return ret;
+
+	dmi_dev = kzalloc_obj(*dmi_dev);
+	if (!dmi_dev) {
+		ret = -ENOMEM;
+		goto fail_class_unregister;
+	}
+
+	dmi_dev->class = &dmi_class;
+	dev_set_name(dmi_dev, "id");
+	dmi_dev->groups = sys_dmi_attribute_groups;
+
+	ret = device_register(dmi_dev);
+	if (ret)
+		goto fail_put_dmi_dev;
+
+	return 0;
+
+fail_put_dmi_dev:
+	put_device(dmi_dev);
+
+fail_class_unregister:
+	class_unregister(&dmi_class);
+
+	return ret;
+}
+
+arch_initcall(dmi_id_init);