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)

2 files changed, 381 insertions, 0 deletions

diff --git a/drivers/accessibility/braille/Makefile b/drivers/accessibility/braille/Makefile
new file mode 100644
index 000000000..fa4b87338
--- /dev/null
+++ b/drivers/accessibility/braille/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_A11Y_BRAILLE_CONSOLE)		+= braille_console.o
diff --git a/drivers/accessibility/braille/braille_console.c b/drivers/accessibility/braille/braille_console.c
new file mode 100644
index 000000000..06b43b678
--- /dev/null
+++ b/drivers/accessibility/braille/braille_console.c
@@ -0,0 +1,379 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Minimalistic braille device kernel support.
+ *
+ * By default, shows console messages on the braille device.
+ * Pressing Insert switches to VC browsing.
+ *
+ *  Copyright (C) Samuel Thibault <samuel.thibault@ens-lyon.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/console.h>
+#include <linux/notifier.h>
+
+#include <linux/selection.h>
+#include <linux/vt_kern.h>
+#include <linux/consolemap.h>
+
+#include <linux/keyboard.h>
+#include <linux/kbd_kern.h>
+#include <linux/input.h>
+
+MODULE_AUTHOR("samuel.thibault@ens-lyon.org");
+MODULE_DESCRIPTION("braille device");
+
+/*
+ * Braille device support part.
+ */
+
+/* Emit various sounds */
+static bool sound;
+module_param(sound, bool, 0);
+MODULE_PARM_DESC(sound, "emit sounds");
+
+static void beep(unsigned int freq)
+{
+	if (sound)
+		kd_mksound(freq, HZ/10);
+}
+
+/* mini console */
+#define WIDTH 40
+#define BRAILLE_KEY KEY_INSERT
+static u16 console_buf[WIDTH];
+static int console_cursor;
+
+/* mini view of VC */
+static int vc_x, vc_y, lastvc_x, lastvc_y;
+
+/* show console ? (or show VC) */
+static int console_show = 1;
+/* pending newline ? */
+static int console_newline = 1;
+static int lastVC = -1;
+
+static struct console *braille_co;
+
+/* Very VisioBraille-specific */
+static void braille_write(u16 *buf)
+{
+	static u16 lastwrite[WIDTH];
+	unsigned char data[1 + 1 + 2*WIDTH + 2 + 1], csum = 0, *c;
+	u16 out;
+	int i;
+
+	if (!braille_co)
+		return;
+
+	if (!memcmp(lastwrite, buf, WIDTH * sizeof(*buf)))
+		return;
+	memcpy(lastwrite, buf, WIDTH * sizeof(*buf));
+
+#define SOH 1
+#define STX 2
+#define ETX 2
+#define EOT 4
+#define ENQ 5
+	data[0] = STX;
+	data[1] = '>';
+	csum ^= '>';
+	c = &data[2];
+	for (i = 0; i < WIDTH; i++) {
+		out = buf[i];
+		if (out >= 0x100)
+			out = '?';
+		else if (out == 0x00)
+			out = ' ';
+		csum ^= out;
+		if (out <= 0x05) {
+			*c++ = SOH;
+			out |= 0x40;
+		}
+		*c++ = out;
+	}
+
+	if (csum <= 0x05) {
+		*c++ = SOH;
+		csum |= 0x40;
+	}
+	*c++ = csum;
+	*c++ = ETX;
+
+	braille_co->write(braille_co, data, c - data);
+}
+
+/* Follow the VC cursor*/
+static void vc_follow_cursor(struct vc_data *vc)
+{
+	vc_x = vc->state.x - (vc->state.x % WIDTH);
+	vc_y = vc->state.y;
+	lastvc_x = vc->state.x;
+	lastvc_y = vc->state.y;
+}
+
+/* Maybe the VC cursor moved, if so follow it */
+static void vc_maybe_cursor_moved(struct vc_data *vc)
+{
+	if (vc->state.x != lastvc_x || vc->state.y != lastvc_y)
+		vc_follow_cursor(vc);
+}
+
+/* Show portion of VC at vc_x, vc_y */
+static void vc_refresh(struct vc_data *vc)
+{
+	u16 buf[WIDTH];
+	int i;
+
+	for (i = 0; i < WIDTH; i++) {
+		u16 glyph = screen_glyph(vc,
+				2 * (vc_x + i) + vc_y * vc->vc_size_row);
+		buf[i] = inverse_translate(vc, glyph, true);
+	}
+	braille_write(buf);
+}
+
+/*
+ * Link to keyboard
+ */
+
+static int keyboard_notifier_call(struct notifier_block *blk,
+				  unsigned long code, void *_param)
+{
+	struct keyboard_notifier_param *param = _param;
+	struct vc_data *vc = param->vc;
+	int ret = NOTIFY_OK;
+
+	if (!param->down)
+		return ret;
+
+	switch (code) {
+	case KBD_KEYCODE:
+		if (console_show) {
+			if (param->value == BRAILLE_KEY) {
+				console_show = 0;
+				beep(880);
+				vc_maybe_cursor_moved(vc);
+				vc_refresh(vc);
+				ret = NOTIFY_STOP;
+			}
+		} else {
+			ret = NOTIFY_STOP;
+			switch (param->value) {
+			case KEY_INSERT:
+				beep(440);
+				console_show = 1;
+				lastVC = -1;
+				braille_write(console_buf);
+				break;
+			case KEY_LEFT:
+				if (vc_x > 0) {
+					vc_x -= WIDTH;
+					if (vc_x < 0)
+						vc_x = 0;
+				} else if (vc_y >= 1) {
+					beep(880);
+					vc_y--;
+					vc_x = vc->vc_cols-WIDTH;
+				} else
+					beep(220);
+				break;
+			case KEY_RIGHT:
+				if (vc_x + WIDTH < vc->vc_cols) {
+					vc_x += WIDTH;
+				} else if (vc_y + 1 < vc->vc_rows) {
+					beep(880);
+					vc_y++;
+					vc_x = 0;
+				} else
+					beep(220);
+				break;
+			case KEY_DOWN:
+				if (vc_y + 1 < vc->vc_rows)
+					vc_y++;
+				else
+					beep(220);
+				break;
+			case KEY_UP:
+				if (vc_y >= 1)
+					vc_y--;
+				else
+					beep(220);
+				break;
+			case KEY_HOME:
+				vc_follow_cursor(vc);
+				break;
+			case KEY_PAGEUP:
+				vc_x = 0;
+				vc_y = 0;
+				break;
+			case KEY_PAGEDOWN:
+				vc_x = 0;
+				vc_y = vc->vc_rows-1;
+				break;
+			default:
+				ret = NOTIFY_OK;
+				break;
+			}
+			if (ret == NOTIFY_STOP)
+				vc_refresh(vc);
+		}
+		break;
+	case KBD_POST_KEYSYM:
+	{
+		unsigned char type = KTYP(param->value) - 0xf0;
+
+		if (type == KT_SPEC) {
+			unsigned char val = KVAL(param->value);
+			int on_off = -1;
+
+			switch (val) {
+			case KVAL(K_CAPS):
+				on_off = vt_get_leds(fg_console, VC_CAPSLOCK);
+				break;
+			case KVAL(K_NUM):
+				on_off = vt_get_leds(fg_console, VC_NUMLOCK);
+				break;
+			case KVAL(K_HOLD):
+				on_off = vt_get_leds(fg_console, VC_SCROLLOCK);
+				break;
+			}
+			if (on_off == 1)
+				beep(880);
+			else if (on_off == 0)
+				beep(440);
+		}
+	}
+		break;
+	case KBD_UNBOUND_KEYCODE:
+	case KBD_UNICODE:
+	case KBD_KEYSYM:
+		/* Unused */
+		break;
+	}
+	return ret;
+}
+
+static struct notifier_block keyboard_notifier_block = {
+	.notifier_call = keyboard_notifier_call,
+};
+
+static int vt_notifier_call(struct notifier_block *blk,
+			    unsigned long code, void *_param)
+{
+	struct vt_notifier_param *param = _param;
+	struct vc_data *vc = param->vc;
+
+	switch (code) {
+	case VT_ALLOCATE:
+		break;
+	case VT_DEALLOCATE:
+		break;
+	case VT_WRITE:
+	{
+		unsigned char c = param->c;
+
+		if (vc->vc_num != fg_console)
+			break;
+		switch (c) {
+		case '\b':
+		case 127:
+			if (console_cursor > 0) {
+				console_cursor--;
+				console_buf[console_cursor] = ' ';
+			}
+			break;
+		case '\n':
+		case '\v':
+		case '\f':
+		case '\r':
+			console_newline = 1;
+			break;
+		case '\t':
+			c = ' ';
+			fallthrough;
+		default:
+			if (c < 32)
+				/* Ignore other control sequences */
+				break;
+			if (console_newline) {
+				memset(console_buf, 0, sizeof(console_buf));
+				console_cursor = 0;
+				console_newline = 0;
+			}
+			if (console_cursor == WIDTH)
+				memmove(console_buf, &console_buf[1],
+					(WIDTH-1) * sizeof(*console_buf));
+			else
+				console_cursor++;
+			console_buf[console_cursor-1] = c;
+			break;
+		}
+		if (console_show)
+			braille_write(console_buf);
+		else {
+			vc_maybe_cursor_moved(vc);
+			vc_refresh(vc);
+		}
+		break;
+	}
+	case VT_UPDATE:
+		/* Maybe a VT switch, flush */
+		if (console_show) {
+			if (vc->vc_num != lastVC) {
+				lastVC = vc->vc_num;
+				memset(console_buf, 0, sizeof(console_buf));
+				console_cursor = 0;
+				braille_write(console_buf);
+			}
+		} else {
+			vc_maybe_cursor_moved(vc);
+			vc_refresh(vc);
+		}
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block vt_notifier_block = {
+	.notifier_call = vt_notifier_call,
+};
+
+/*
+ * Called from printk.c when console=brl is given
+ */
+
+int braille_register_console(struct console *console, int index,
+		char *console_options, char *braille_options)
+{
+	int ret;
+
+	if (!console_options)
+		/* Only support VisioBraille for now */
+		console_options = "57600o8";
+	if (braille_co)
+		return -ENODEV;
+	if (console->setup) {
+		ret = console->setup(console, console_options);
+		if (ret != 0)
+			return ret;
+	}
+	console->flags |= CON_ENABLED;
+	console->index = index;
+	braille_co = console;
+	register_keyboard_notifier(&keyboard_notifier_block);
+	register_vt_notifier(&vt_notifier_block);
+	return 1;
+}
+
+int braille_unregister_console(struct console *console)
+{
+	if (braille_co != console)
+		return -EINVAL;
+	unregister_keyboard_notifier(&keyboard_notifier_block);
+	unregister_vt_notifier(&vt_notifier_block);
+	braille_co = NULL;
+	return 1;
+}