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-pcf8583.c | 317 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 317 insertions(+) create mode 100644 drivers/rtc/rtc-pcf8583.c (limited to 'drivers/rtc/rtc-pcf8583.c') diff --git a/drivers/rtc/rtc-pcf8583.c b/drivers/rtc/rtc-pcf8583.c new file mode 100644 index 000000000..df5e20cbc --- /dev/null +++ b/drivers/rtc/rtc-pcf8583.c @@ -0,0 +1,317 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * drivers/rtc/rtc-pcf8583.c + * + * Copyright (C) 2000 Russell King + * Copyright (C) 2008 Wolfram Sang & Juergen Beisert, Pengutronix + * + * Driver for PCF8583 RTC & RAM chip + * + * Converted to the generic RTC susbsystem by G. Liakhovetski (2006) + */ +#include +#include +#include +#include +#include +#include +#include +#include + +struct rtc_mem { + unsigned int loc; + unsigned int nr; + unsigned char *data; +}; + +struct pcf8583 { + struct rtc_device *rtc; + unsigned char ctrl; +}; + +#define CTRL_STOP 0x80 +#define CTRL_HOLD 0x40 +#define CTRL_32KHZ 0x00 +#define CTRL_MASK 0x08 +#define CTRL_ALARMEN 0x04 +#define CTRL_ALARM 0x02 +#define CTRL_TIMER 0x01 + + +static struct i2c_driver pcf8583_driver; + +#define get_ctrl(x) ((struct pcf8583 *)i2c_get_clientdata(x))->ctrl +#define set_ctrl(x, v) get_ctrl(x) = v + +#define CMOS_YEAR (64 + 128) +#define CMOS_CHECKSUM (63) + +static int pcf8583_get_datetime(struct i2c_client *client, struct rtc_time *dt) +{ + unsigned char buf[8], addr[1] = { 1 }; + struct i2c_msg msgs[2] = { + { + .addr = client->addr, + .flags = 0, + .len = 1, + .buf = addr, + }, { + .addr = client->addr, + .flags = I2C_M_RD, + .len = 6, + .buf = buf, + } + }; + int ret; + + memset(buf, 0, sizeof(buf)); + + ret = i2c_transfer(client->adapter, msgs, 2); + if (ret == 2) { + dt->tm_year = buf[4] >> 6; + dt->tm_wday = buf[5] >> 5; + + buf[4] &= 0x3f; + buf[5] &= 0x1f; + + dt->tm_sec = bcd2bin(buf[1]); + dt->tm_min = bcd2bin(buf[2]); + dt->tm_hour = bcd2bin(buf[3]); + dt->tm_mday = bcd2bin(buf[4]); + dt->tm_mon = bcd2bin(buf[5]) - 1; + } + + return ret == 2 ? 0 : -EIO; +} + +static int pcf8583_set_datetime(struct i2c_client *client, struct rtc_time *dt, int datetoo) +{ + unsigned char buf[8]; + int ret, len = 6; + + buf[0] = 0; + buf[1] = get_ctrl(client) | 0x80; + buf[2] = 0; + buf[3] = bin2bcd(dt->tm_sec); + buf[4] = bin2bcd(dt->tm_min); + buf[5] = bin2bcd(dt->tm_hour); + + if (datetoo) { + len = 8; + buf[6] = bin2bcd(dt->tm_mday) | (dt->tm_year << 6); + buf[7] = bin2bcd(dt->tm_mon + 1) | (dt->tm_wday << 5); + } + + ret = i2c_master_send(client, (char *)buf, len); + if (ret != len) + return -EIO; + + buf[1] = get_ctrl(client); + ret = i2c_master_send(client, (char *)buf, 2); + + return ret == 2 ? 0 : -EIO; +} + +static int pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl) +{ + *ctrl = get_ctrl(client); + return 0; +} + +static int pcf8583_set_ctrl(struct i2c_client *client, unsigned char *ctrl) +{ + unsigned char buf[2]; + + buf[0] = 0; + buf[1] = *ctrl; + set_ctrl(client, *ctrl); + + return i2c_master_send(client, (char *)buf, 2); +} + +static int pcf8583_read_mem(struct i2c_client *client, struct rtc_mem *mem) +{ + unsigned char addr[1]; + struct i2c_msg msgs[2] = { + { + .addr = client->addr, + .flags = 0, + .len = 1, + .buf = addr, + }, { + .addr = client->addr, + .flags = I2C_M_RD, + .len = mem->nr, + .buf = mem->data, + } + }; + + if (mem->loc < 8) + return -EINVAL; + + addr[0] = mem->loc; + + return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO; +} + +static int pcf8583_write_mem(struct i2c_client *client, struct rtc_mem *mem) +{ + unsigned char buf[9]; + int ret; + + if (mem->loc < 8 || mem->nr > 8) + return -EINVAL; + + buf[0] = mem->loc; + memcpy(buf + 1, mem->data, mem->nr); + + ret = i2c_master_send(client, buf, mem->nr + 1); + return ret == mem->nr + 1 ? 0 : -EIO; +} + +static int pcf8583_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct i2c_client *client = to_i2c_client(dev); + unsigned char ctrl, year[2]; + struct rtc_mem mem = { + .loc = CMOS_YEAR, + .nr = sizeof(year), + .data = year + }; + int real_year, year_offset, err; + + /* + * Ensure that the RTC is running. + */ + pcf8583_get_ctrl(client, &ctrl); + if (ctrl & (CTRL_STOP | CTRL_HOLD)) { + unsigned char new_ctrl = ctrl & ~(CTRL_STOP | CTRL_HOLD); + + dev_warn(dev, "resetting control %02x -> %02x\n", + ctrl, new_ctrl); + + err = pcf8583_set_ctrl(client, &new_ctrl); + if (err < 0) + return err; + } + + if (pcf8583_get_datetime(client, tm) || + pcf8583_read_mem(client, &mem)) + return -EIO; + + real_year = year[0]; + + /* + * The RTC year holds the LSB two bits of the current + * year, which should reflect the LSB two bits of the + * CMOS copy of the year. Any difference indicates + * that we have to correct the CMOS version. + */ + year_offset = tm->tm_year - (real_year & 3); + if (year_offset < 0) + /* + * RTC year wrapped. Adjust it appropriately. + */ + year_offset += 4; + + tm->tm_year = (real_year + year_offset + year[1] * 100) - 1900; + + return 0; +} + +static int pcf8583_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct i2c_client *client = to_i2c_client(dev); + unsigned char year[2], chk; + struct rtc_mem cmos_year = { + .loc = CMOS_YEAR, + .nr = sizeof(year), + .data = year + }; + struct rtc_mem cmos_check = { + .loc = CMOS_CHECKSUM, + .nr = 1, + .data = &chk + }; + unsigned int proper_year = tm->tm_year + 1900; + int ret; + + /* + * The RTC's own 2-bit year must reflect the least + * significant two bits of the CMOS year. + */ + + ret = pcf8583_set_datetime(client, tm, 1); + if (ret) + return ret; + + ret = pcf8583_read_mem(client, &cmos_check); + if (ret) + return ret; + + ret = pcf8583_read_mem(client, &cmos_year); + if (ret) + return ret; + + chk -= year[1] + year[0]; + + year[1] = proper_year / 100; + year[0] = proper_year % 100; + + chk += year[1] + year[0]; + + ret = pcf8583_write_mem(client, &cmos_year); + + if (ret) + return ret; + + ret = pcf8583_write_mem(client, &cmos_check); + + return ret; +} + +static const struct rtc_class_ops pcf8583_rtc_ops = { + .read_time = pcf8583_rtc_read_time, + .set_time = pcf8583_rtc_set_time, +}; + +static int pcf8583_probe(struct i2c_client *client) +{ + struct pcf8583 *pcf8583; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) + return -ENODEV; + + pcf8583 = devm_kzalloc(&client->dev, sizeof(struct pcf8583), + GFP_KERNEL); + if (!pcf8583) + return -ENOMEM; + + i2c_set_clientdata(client, pcf8583); + + pcf8583->rtc = devm_rtc_device_register(&client->dev, + pcf8583_driver.driver.name, + &pcf8583_rtc_ops, THIS_MODULE); + + return PTR_ERR_OR_ZERO(pcf8583->rtc); +} + +static const struct i2c_device_id pcf8583_id[] = { + { .name = "pcf8583" }, + { } +}; +MODULE_DEVICE_TABLE(i2c, pcf8583_id); + +static struct i2c_driver pcf8583_driver = { + .driver = { + .name = "pcf8583", + }, + .probe = pcf8583_probe, + .id_table = pcf8583_id, +}; + +module_i2c_driver(pcf8583_driver); + +MODULE_AUTHOR("Russell King"); +MODULE_DESCRIPTION("PCF8583 I2C RTC driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1