From 106b4a2a78b2a2f14885604891957b84bba502db Mon Sep 17 00:00:00 2001 From: Adrian Betschart Date: Fri, 11 Sep 2026 17:13:14 +0200 Subject: drm/amd/display: Try RGB before YCbCr 4:4:4 in stream validation 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 Assisted-by: Claude Code:claude-fable-5-1 Signed-off-by: Adrian Betschart Reviewed-by: Fangzhi Zuo Tested-by: Adolfo Rodrigues Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher (cherry picked from commit 7de432bc753133764dc40d37f9388da56de251e7) --- drivers/rtc/rtc-max6902.c | 154 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 154 insertions(+) create mode 100644 drivers/rtc/rtc-max6902.c (limited to 'drivers/rtc/rtc-max6902.c') diff --git a/drivers/rtc/rtc-max6902.c b/drivers/rtc/rtc-max6902.c new file mode 100644 index 000000000..daaeb6fb6 --- /dev/null +++ b/drivers/rtc/rtc-max6902.c @@ -0,0 +1,154 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* drivers/rtc/rtc-max6902.c + * + * Copyright (C) 2006 8D Technologies inc. + * Copyright (C) 2004 Compulab Ltd. + * + * Driver for MAX6902 spi RTC + */ + +#include +#include +#include +#include +#include +#include +#include + +#define MAX6902_REG_SECONDS 0x01 +#define MAX6902_REG_MINUTES 0x03 +#define MAX6902_REG_HOURS 0x05 +#define MAX6902_REG_DATE 0x07 +#define MAX6902_REG_MONTH 0x09 +#define MAX6902_REG_DAY 0x0B +#define MAX6902_REG_YEAR 0x0D +#define MAX6902_REG_CONTROL 0x0F +#define MAX6902_REG_CENTURY 0x13 + +static int max6902_set_reg(struct device *dev, unsigned char address, + unsigned char data) +{ + struct spi_device *spi = to_spi_device(dev); + unsigned char buf[2]; + + /* MSB must be '0' to write */ + buf[0] = address & 0x7f; + buf[1] = data; + + return spi_write_then_read(spi, buf, 2, NULL, 0); +} + +static int max6902_get_reg(struct device *dev, unsigned char address, + unsigned char *data) +{ + struct spi_device *spi = to_spi_device(dev); + + /* Set MSB to indicate read */ + *data = address | 0x80; + + return spi_write_then_read(spi, data, 1, data, 1); +} + +static int max6902_read_time(struct device *dev, struct rtc_time *dt) +{ + int err, century; + struct spi_device *spi = to_spi_device(dev); + unsigned char buf[8]; + + buf[0] = 0xbf; /* Burst read */ + + err = spi_write_then_read(spi, buf, 1, buf, 8); + if (err != 0) + return err; + + /* The chip sends data in this order: + * Seconds, Minutes, Hours, Date, Month, Day, Year */ + dt->tm_sec = bcd2bin(buf[0]); + dt->tm_min = bcd2bin(buf[1]); + dt->tm_hour = bcd2bin(buf[2]); + dt->tm_mday = bcd2bin(buf[3]); + dt->tm_mon = bcd2bin(buf[4]) - 1; + dt->tm_wday = bcd2bin(buf[5]); + dt->tm_year = bcd2bin(buf[6]); + + /* Read century */ + err = max6902_get_reg(dev, MAX6902_REG_CENTURY, &buf[0]); + if (err != 0) + return err; + + century = bcd2bin(buf[0]) * 100; + + dt->tm_year += century; + dt->tm_year -= 1900; + + return 0; +} + +static int max6902_set_time(struct device *dev, struct rtc_time *dt) +{ + dt->tm_year = dt->tm_year + 1900; + + /* Remove write protection */ + max6902_set_reg(dev, MAX6902_REG_CONTROL, 0); + + max6902_set_reg(dev, MAX6902_REG_SECONDS, bin2bcd(dt->tm_sec)); + max6902_set_reg(dev, MAX6902_REG_MINUTES, bin2bcd(dt->tm_min)); + max6902_set_reg(dev, MAX6902_REG_HOURS, bin2bcd(dt->tm_hour)); + + max6902_set_reg(dev, MAX6902_REG_DATE, bin2bcd(dt->tm_mday)); + max6902_set_reg(dev, MAX6902_REG_MONTH, bin2bcd(dt->tm_mon + 1)); + max6902_set_reg(dev, MAX6902_REG_DAY, bin2bcd(dt->tm_wday)); + max6902_set_reg(dev, MAX6902_REG_YEAR, bin2bcd(dt->tm_year % 100)); + max6902_set_reg(dev, MAX6902_REG_CENTURY, bin2bcd(dt->tm_year / 100)); + + /* Compulab used a delay here. However, the datasheet + * does not mention a delay being required anywhere... */ + /* delay(2000); */ + + /* Write protect */ + max6902_set_reg(dev, MAX6902_REG_CONTROL, 0x80); + + return 0; +} + +static const struct rtc_class_ops max6902_rtc_ops = { + .read_time = max6902_read_time, + .set_time = max6902_set_time, +}; + +static int max6902_probe(struct spi_device *spi) +{ + struct rtc_device *rtc; + unsigned char tmp; + int res; + + spi->mode = SPI_MODE_3; + spi->bits_per_word = 8; + spi_setup(spi); + + res = max6902_get_reg(&spi->dev, MAX6902_REG_SECONDS, &tmp); + if (res != 0) + return res; + + rtc = devm_rtc_device_register(&spi->dev, "max6902", + &max6902_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + spi_set_drvdata(spi, rtc); + return 0; +} + +static struct spi_driver max6902_driver = { + .driver = { + .name = "rtc-max6902", + }, + .probe = max6902_probe, +}; + +module_spi_driver(max6902_driver); + +MODULE_DESCRIPTION("max6902 spi RTC driver"); +MODULE_AUTHOR("Raphael Assenat"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("spi:rtc-max6902"); -- cgit v1.3.1