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/base/regmap/regmap-raw-ram.c | 144 +++++++++++++++++++++++++++++++++++ 1 file changed, 144 insertions(+) create mode 100644 drivers/base/regmap/regmap-raw-ram.c (limited to 'drivers/base/regmap/regmap-raw-ram.c') diff --git a/drivers/base/regmap/regmap-raw-ram.c b/drivers/base/regmap/regmap-raw-ram.c new file mode 100644 index 000000000..60d6e95cd --- /dev/null +++ b/drivers/base/regmap/regmap-raw-ram.c @@ -0,0 +1,144 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// Register map access API - Memory region with raw access +// +// This is intended for testing only +// +// Copyright (c) 2023, Arm Ltd + +#include +#include +#include +#include +#include +#include +#include + +#include "internal.h" + +static unsigned int decode_reg(enum regmap_endian endian, const void *reg) +{ + const u16 *r = reg; + + if (endian == REGMAP_ENDIAN_BIG) + return be16_to_cpu(*r); + else + return le16_to_cpu(*r); +} + +static int regmap_raw_ram_gather_write(void *context, + const void *reg, size_t reg_len, + const void *val, size_t val_len) +{ + struct regmap_ram_data *data = context; + unsigned int r; + u16 *our_buf = (u16 *)data->vals; + int i; + + if (reg_len != 2) + return -EINVAL; + if (val_len % 2) + return -EINVAL; + + r = decode_reg(data->reg_endian, reg); + if (data->noinc_reg && data->noinc_reg(data, r)) { + memcpy(&our_buf[r], val + val_len - 2, 2); + data->written[r] = true; + } else { + memcpy(&our_buf[r], val, val_len); + + for (i = 0; i < val_len / 2; i++) + data->written[r + i] = true; + } + + return 0; +} + +static int regmap_raw_ram_write(void *context, const void *data, size_t count) +{ + return regmap_raw_ram_gather_write(context, data, 2, + data + 2, count - 2); +} + +static int regmap_raw_ram_read(void *context, + const void *reg, size_t reg_len, + void *val, size_t val_len) +{ + struct regmap_ram_data *data = context; + unsigned int r; + u16 *our_buf = (u16 *)data->vals; + int i; + + if (reg_len != 2) + return -EINVAL; + if (val_len % 2) + return -EINVAL; + + r = decode_reg(data->reg_endian, reg); + if (data->noinc_reg && data->noinc_reg(data, r)) { + for (i = 0; i < val_len; i += 2) + memcpy(val + i, &our_buf[r], 2); + data->read[r] = true; + } else { + memcpy(val, &our_buf[r], val_len); + + for (i = 0; i < val_len / 2; i++) + data->read[r + i] = true; + } + + return 0; +} + +static void regmap_raw_ram_free_context(void *context) +{ + struct regmap_ram_data *data = context; + + kfree(data->vals); + kfree(data->read); + kfree(data->written); + kfree(data); +} + +static const struct regmap_bus regmap_raw_ram = { + .fast_io = true, + .write = regmap_raw_ram_write, + .gather_write = regmap_raw_ram_gather_write, + .read = regmap_raw_ram_read, + .free_context = regmap_raw_ram_free_context, +}; + +struct regmap *__regmap_init_raw_ram(struct device *dev, + const struct regmap_config *config, + struct regmap_ram_data *data, + struct lock_class_key *lock_key, + const char *lock_name) +{ + struct regmap *map; + + if (config->reg_bits != 16) + return ERR_PTR(-EINVAL); + + if (!config->max_register) { + pr_crit("No max_register specified for RAM regmap\n"); + return ERR_PTR(-EINVAL); + } + + data->read = kzalloc_objs(bool, config->max_register + 1); + if (!data->read) + return ERR_PTR(-ENOMEM); + + data->written = kzalloc_objs(bool, config->max_register + 1); + if (!data->written) + return ERR_PTR(-ENOMEM); + + data->reg_endian = config->reg_format_endian; + + map = __regmap_init(dev, ®map_raw_ram, data, config, + lock_key, lock_name); + + return map; +} +EXPORT_SYMBOL_GPL(__regmap_init_raw_ram); + +MODULE_DESCRIPTION("Register map access API - Memory region with raw access"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1