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, 174 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-pl030.c b/drivers/rtc/rtc-pl030.c
new file mode 100644
index 000000000..5caaa714f
--- /dev/null
+++ b/drivers/rtc/rtc-pl030.c
@@ -0,0 +1,174 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/drivers/rtc/rtc-pl030.c
+ *
+ *  Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
+ */
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/amba/bus.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+
+#define RTC_DR		(0)
+#define RTC_MR		(4)
+#define RTC_STAT	(8)
+#define RTC_EOI		(8)
+#define RTC_LR		(12)
+#define RTC_CR		(16)
+#define RTC_CR_MIE	(1 << 0)
+
+struct pl030_rtc {
+	void __iomem		*base;
+};
+
+static irqreturn_t pl030_interrupt(int irq, void *dev_id)
+{
+	struct pl030_rtc *rtc = dev_id;
+	writel(0, rtc->base + RTC_EOI);
+	return IRQ_HANDLED;
+}
+
+static int pl030_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct pl030_rtc *rtc = dev_get_drvdata(dev);
+
+	rtc_time64_to_tm(readl(rtc->base + RTC_MR), &alrm->time);
+	return 0;
+}
+
+static int pl030_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct pl030_rtc *rtc = dev_get_drvdata(dev);
+
+	writel(rtc_tm_to_time64(&alrm->time), rtc->base + RTC_MR);
+
+	return 0;
+}
+
+static int pl030_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct pl030_rtc *rtc = dev_get_drvdata(dev);
+
+	rtc_time64_to_tm(readl(rtc->base + RTC_DR), tm);
+
+	return 0;
+}
+
+/*
+ * Set the RTC time.  Unfortunately, we can't accurately set
+ * the point at which the counter updates.
+ *
+ * Also, since RTC_LR is transferred to RTC_CR on next rising
+ * edge of the 1Hz clock, we must write the time one second
+ * in advance.
+ */
+static int pl030_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct pl030_rtc *rtc = dev_get_drvdata(dev);
+
+	writel(rtc_tm_to_time64(tm) + 1, rtc->base + RTC_LR);
+
+	return 0;
+}
+
+static const struct rtc_class_ops pl030_ops = {
+	.read_time	= pl030_read_time,
+	.set_time	= pl030_set_time,
+	.read_alarm	= pl030_read_alarm,
+	.set_alarm	= pl030_set_alarm,
+};
+
+static int pl030_probe(struct amba_device *dev, const struct amba_id *id)
+{
+	struct pl030_rtc *rtc;
+	int ret;
+	struct rtc_device *rtc_dev;
+
+	ret = amba_request_regions(dev, NULL);
+	if (ret)
+		goto err_req;
+
+	rtc = devm_kzalloc(&dev->dev, sizeof(*rtc), GFP_KERNEL);
+	if (!rtc) {
+		ret = -ENOMEM;
+		goto err_rtc;
+	}
+
+	rtc_dev = devm_rtc_allocate_device(&dev->dev);
+	if (IS_ERR(rtc_dev)) {
+		ret = PTR_ERR(rtc_dev);
+		goto err_rtc;
+	}
+
+	rtc_dev->ops = &pl030_ops;
+	rtc_dev->range_max = U32_MAX;
+	rtc->base = ioremap(dev->res.start, resource_size(&dev->res));
+	if (!rtc->base) {
+		ret = -ENOMEM;
+		goto err_rtc;
+	}
+
+	__raw_writel(0, rtc->base + RTC_CR);
+	__raw_writel(0, rtc->base + RTC_EOI);
+
+	amba_set_drvdata(dev, rtc);
+
+	ret = request_irq(dev->irq[0], pl030_interrupt, 0,
+			  "rtc-pl030", rtc);
+	if (ret)
+		goto err_irq;
+
+	ret = devm_rtc_register_device(rtc_dev);
+	if (ret)
+		goto err_reg;
+
+	return 0;
+
+ err_reg:
+	free_irq(dev->irq[0], rtc);
+ err_irq:
+	iounmap(rtc->base);
+ err_rtc:
+	amba_release_regions(dev);
+ err_req:
+	return ret;
+}
+
+static void pl030_remove(struct amba_device *dev)
+{
+	struct pl030_rtc *rtc = amba_get_drvdata(dev);
+
+	writel(0, rtc->base + RTC_CR);
+
+	free_irq(dev->irq[0], rtc);
+	iounmap(rtc->base);
+	amba_release_regions(dev);
+}
+
+static const struct amba_id pl030_ids[] = {
+	{
+		.id	= 0x00041030,
+		.mask	= 0x000fffff,
+	},
+	{ 0, 0 },
+};
+
+MODULE_DEVICE_TABLE(amba, pl030_ids);
+
+static struct amba_driver pl030_driver = {
+	.drv		= {
+		.name	= "rtc-pl030",
+	},
+	.probe		= pl030_probe,
+	.remove		= pl030_remove,
+	.id_table	= pl030_ids,
+};
+
+module_amba_driver(pl030_driver);
+
+MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
+MODULE_DESCRIPTION("ARM AMBA PL030 RTC Driver");
+MODULE_LICENSE("GPL");