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, 158 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-em3027.c b/drivers/rtc/rtc-em3027.c
new file mode 100644
index 000000000..d555e5d59
--- /dev/null
+++ b/drivers/rtc/rtc-em3027.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * An rtc/i2c driver for the EM Microelectronic EM3027
+ * Copyright 2011 CompuLab, Ltd.
+ *
+ * Author: Mike Rapoport <mike@compulab.co.il>
+ *
+ * Based on rtc-ds1672.c by Alessandro Zummo <a.zummo@towertech.it>
+ */
+
+#include <linux/i2c.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+/* Registers */
+#define EM3027_REG_ON_OFF_CTRL	0x00
+#define EM3027_REG_IRQ_CTRL	0x01
+#define EM3027_REG_IRQ_FLAGS	0x02
+#define EM3027_REG_STATUS	0x03
+#define EM3027_REG_RST_CTRL	0x04
+
+#define EM3027_REG_WATCH_SEC	0x08
+#define EM3027_REG_WATCH_MIN	0x09
+#define EM3027_REG_WATCH_HOUR	0x0a
+#define EM3027_REG_WATCH_DATE	0x0b
+#define EM3027_REG_WATCH_DAY	0x0c
+#define EM3027_REG_WATCH_MON	0x0d
+#define EM3027_REG_WATCH_YEAR	0x0e
+
+#define EM3027_REG_ALARM_SEC	0x10
+#define EM3027_REG_ALARM_MIN	0x11
+#define EM3027_REG_ALARM_HOUR	0x12
+#define EM3027_REG_ALARM_DATE	0x13
+#define EM3027_REG_ALARM_DAY	0x14
+#define EM3027_REG_ALARM_MON	0x15
+#define EM3027_REG_ALARM_YEAR	0x16
+
+static struct i2c_driver em3027_driver;
+
+static int em3027_get_time(struct device *dev, struct rtc_time *tm)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+
+	unsigned char addr = EM3027_REG_WATCH_SEC;
+	unsigned char buf[7];
+
+	struct i2c_msg msgs[] = {
+		{/* setup read addr */
+			.addr = client->addr,
+			.len = 1,
+			.buf = &addr
+		},
+		{/* read time/date */
+			.addr = client->addr,
+			.flags = I2C_M_RD,
+			.len = 7,
+			.buf = buf
+		},
+	};
+
+	/* read time/date registers */
+	if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
+		dev_err(&client->dev, "%s: read error\n", __func__);
+		return -EIO;
+	}
+
+	tm->tm_sec	= bcd2bin(buf[0]);
+	tm->tm_min	= bcd2bin(buf[1]);
+	tm->tm_hour	= bcd2bin(buf[2]);
+	tm->tm_mday	= bcd2bin(buf[3]);
+	tm->tm_wday	= bcd2bin(buf[4]);
+	tm->tm_mon	= bcd2bin(buf[5]) - 1;
+	tm->tm_year	= bcd2bin(buf[6]) + 100;
+
+	return 0;
+}
+
+static int em3027_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	unsigned char buf[8];
+
+	struct i2c_msg msg = {
+		.addr = client->addr,
+		.len = 8,
+		.buf = buf,	/* write time/date */
+	};
+
+	buf[0] = EM3027_REG_WATCH_SEC;
+	buf[1] = bin2bcd(tm->tm_sec);
+	buf[2] = bin2bcd(tm->tm_min);
+	buf[3] = bin2bcd(tm->tm_hour);
+	buf[4] = bin2bcd(tm->tm_mday);
+	buf[5] = bin2bcd(tm->tm_wday);
+	buf[6] = bin2bcd(tm->tm_mon + 1);
+	buf[7] = bin2bcd(tm->tm_year % 100);
+
+	/* write time/date registers */
+	if ((i2c_transfer(client->adapter, &msg, 1)) != 1) {
+		dev_err(&client->dev, "%s: write error\n", __func__);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static const struct rtc_class_ops em3027_rtc_ops = {
+	.read_time = em3027_get_time,
+	.set_time = em3027_set_time,
+};
+
+static int em3027_probe(struct i2c_client *client)
+{
+	struct rtc_device *rtc;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+		return -ENODEV;
+
+	rtc = devm_rtc_device_register(&client->dev, em3027_driver.driver.name,
+				  &em3027_rtc_ops, THIS_MODULE);
+	if (IS_ERR(rtc))
+		return PTR_ERR(rtc);
+
+	i2c_set_clientdata(client, rtc);
+
+	return 0;
+}
+
+static const struct i2c_device_id em3027_id[] = {
+	{ .name = "em3027" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, em3027_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id em3027_of_match[] = {
+	{ .compatible = "emmicro,em3027", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, em3027_of_match);
+#endif
+
+static struct i2c_driver em3027_driver = {
+	.driver = {
+		   .name = "rtc-em3027",
+		   .of_match_table = of_match_ptr(em3027_of_match),
+	},
+	.probe = em3027_probe,
+	.id_table = em3027_id,
+};
+
+module_i2c_driver(em3027_driver);
+
+MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
+MODULE_DESCRIPTION("EM Microelectronic EM3027 RTC driver");
+MODULE_LICENSE("GPL");