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, 202 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-bq4802.c b/drivers/rtc/rtc-bq4802.c
new file mode 100644
index 000000000..472e75668
--- /dev/null
+++ b/drivers/rtc/rtc-bq4802.c
@@ -0,0 +1,202 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* rtc-bq4802.c: TI BQ4802 RTC driver.
+ *
+ * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+#include <linux/slab.h>
+
+MODULE_AUTHOR("David S. Miller <davem@davemloft.net>");
+MODULE_DESCRIPTION("TI BQ4802 RTC driver");
+MODULE_LICENSE("GPL");
+
+struct bq4802 {
+	void __iomem		*regs;
+	unsigned long		ioport;
+	struct rtc_device	*rtc;
+	spinlock_t		lock;
+	struct resource		*r;
+	u8 (*read)(struct bq4802 *, int);
+	void (*write)(struct bq4802 *, int, u8);
+};
+
+static u8 bq4802_read_io(struct bq4802 *p, int off)
+{
+	return inb(p->ioport + off);
+}
+
+static void bq4802_write_io(struct bq4802 *p, int off, u8 val)
+{
+	outb(val, p->ioport + off);
+}
+
+static u8 bq4802_read_mem(struct bq4802 *p, int off)
+{
+	return readb(p->regs + off);
+}
+
+static void bq4802_write_mem(struct bq4802 *p, int off, u8 val)
+{
+	writeb(val, p->regs + off);
+}
+
+static int bq4802_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct bq4802 *p = dev_get_drvdata(dev);
+	unsigned long flags;
+	unsigned int century;
+	u8 val;
+
+	spin_lock_irqsave(&p->lock, flags);
+
+	val = p->read(p, 0x0e);
+	p->write(p, 0xe, val | 0x08);
+
+	tm->tm_sec = p->read(p, 0x00);
+	tm->tm_min = p->read(p, 0x02);
+	tm->tm_hour = p->read(p, 0x04);
+	tm->tm_mday = p->read(p, 0x06);
+	tm->tm_mon = p->read(p, 0x09);
+	tm->tm_year = p->read(p, 0x0a);
+	tm->tm_wday = p->read(p, 0x08);
+	century = p->read(p, 0x0f);
+
+	p->write(p, 0x0e, val);
+
+	spin_unlock_irqrestore(&p->lock, flags);
+
+	tm->tm_sec = bcd2bin(tm->tm_sec);
+	tm->tm_min = bcd2bin(tm->tm_min);
+	tm->tm_hour = bcd2bin(tm->tm_hour);
+	tm->tm_mday = bcd2bin(tm->tm_mday);
+	tm->tm_mon = bcd2bin(tm->tm_mon);
+	tm->tm_year = bcd2bin(tm->tm_year);
+	tm->tm_wday = bcd2bin(tm->tm_wday);
+	century = bcd2bin(century);
+
+	tm->tm_year += (century * 100);
+	tm->tm_year -= 1900;
+
+	tm->tm_mon--;
+
+	return 0;
+}
+
+static int bq4802_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct bq4802 *p = dev_get_drvdata(dev);
+	u8 sec, min, hrs, day, mon, yrs, century, val;
+	unsigned long flags;
+	unsigned int year;
+
+	year = tm->tm_year + 1900;
+	century = year / 100;
+	yrs = year % 100;
+
+	mon = tm->tm_mon + 1;   /* tm_mon starts at zero */
+	day = tm->tm_mday;
+	hrs = tm->tm_hour;
+	min = tm->tm_min;
+	sec = tm->tm_sec;
+
+	sec = bin2bcd(sec);
+	min = bin2bcd(min);
+	hrs = bin2bcd(hrs);
+	day = bin2bcd(day);
+	mon = bin2bcd(mon);
+	yrs = bin2bcd(yrs);
+	century = bin2bcd(century);
+
+	spin_lock_irqsave(&p->lock, flags);
+
+	val = p->read(p, 0x0e);
+	p->write(p, 0x0e, val | 0x08);
+
+	p->write(p, 0x00, sec);
+	p->write(p, 0x02, min);
+	p->write(p, 0x04, hrs);
+	p->write(p, 0x06, day);
+	p->write(p, 0x09, mon);
+	p->write(p, 0x0a, yrs);
+	p->write(p, 0x0f, century);
+
+	p->write(p, 0x0e, val);
+
+	spin_unlock_irqrestore(&p->lock, flags);
+
+	return 0;
+}
+
+static const struct rtc_class_ops bq4802_ops = {
+	.read_time	= bq4802_read_time,
+	.set_time	= bq4802_set_time,
+};
+
+static int bq4802_probe(struct platform_device *pdev)
+{
+	struct bq4802 *p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
+	int err = -ENOMEM;
+
+	if (!p)
+		goto out;
+
+	spin_lock_init(&p->lock);
+
+	p->r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!p->r) {
+		p->r = platform_get_resource(pdev, IORESOURCE_IO, 0);
+		err = -EINVAL;
+		if (!p->r)
+			goto out;
+	}
+	if (p->r->flags & IORESOURCE_IO) {
+		p->ioport = p->r->start;
+		p->read = bq4802_read_io;
+		p->write = bq4802_write_io;
+	} else if (p->r->flags & IORESOURCE_MEM) {
+		p->regs = devm_ioremap(&pdev->dev, p->r->start,
+					resource_size(p->r));
+		if (!p->regs){
+			err = -ENOMEM;
+			goto out;
+		}
+		p->read = bq4802_read_mem;
+		p->write = bq4802_write_mem;
+	} else {
+		err = -EINVAL;
+		goto out;
+	}
+
+	platform_set_drvdata(pdev, p);
+
+	p->rtc = devm_rtc_device_register(&pdev->dev, "bq4802",
+					&bq4802_ops, THIS_MODULE);
+	if (IS_ERR(p->rtc)) {
+		err = PTR_ERR(p->rtc);
+		goto out;
+	}
+
+	err = 0;
+out:
+	return err;
+
+}
+
+/* work with hotplug and coldplug */
+MODULE_ALIAS("platform:rtc-bq4802");
+
+static struct platform_driver bq4802_driver = {
+	.driver		= {
+		.name	= "rtc-bq4802",
+	},
+	.probe		= bq4802_probe,
+};
+
+module_platform_driver(bq4802_driver);