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/misc/cb710/debug.c | 115 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 115 insertions(+) create mode 100644 drivers/misc/cb710/debug.c (limited to 'drivers/misc/cb710/debug.c') diff --git a/drivers/misc/cb710/debug.c b/drivers/misc/cb710/debug.c new file mode 100644 index 000000000..20d672edf --- /dev/null +++ b/drivers/misc/cb710/debug.c @@ -0,0 +1,115 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * cb710/debug.c + * + * Copyright by Michał Mirosław, 2008-2009 + */ +#include +#include +#include + +#define CB710_REG_COUNT 0x80 + +static const u16 allow[CB710_REG_COUNT/16] = { + 0xFFF0, 0xFFFF, 0xFFFF, 0xFFFF, + 0xFFF0, 0xFFFF, 0xFFFF, 0xFFFF, +}; +static const char *const prefix[ARRAY_SIZE(allow)] = { + "MMC", "MMC", "MMC", "MMC", + "MS?", "MS?", "SM?", "SM?" +}; + +static inline int allow_reg_read(unsigned block, unsigned offset, unsigned bits) +{ + unsigned mask = (1 << bits/8) - 1; + offset *= bits/8; + return ((allow[block] >> offset) & mask) == mask; +} + +#define CB710_READ_REGS_TEMPLATE(t) \ +static void cb710_read_regs_##t(void __iomem *iobase, \ + u##t *reg, unsigned select) \ +{ \ + unsigned i, j; \ + \ + for (i = 0; i < ARRAY_SIZE(allow); ++i, reg += 16/(t/8)) { \ + if (!(select & (1 << i))) \ + continue; \ + \ + for (j = 0; j < 0x10/(t/8); ++j) { \ + if (!allow_reg_read(i, j, t)) \ + continue; \ + reg[j] = ioread##t(iobase \ + + (i << 4) + (j * (t/8))); \ + } \ + } \ +} + +static const char cb710_regf_8[] = "%02X"; +static const char cb710_regf_16[] = "%04X"; +static const char cb710_regf_32[] = "%08X"; +static const char cb710_xes[] = "xxxxxxxx"; + +#define CB710_DUMP_REGS_TEMPLATE(t) \ +static void cb710_dump_regs_##t(struct device *dev, \ + const u##t *reg, unsigned select) \ +{ \ + const char *const xp = &cb710_xes[8 - t/4]; \ + const char *const format = cb710_regf_##t; \ + \ + char msg[100], *p; \ + unsigned i, j; \ + \ + for (i = 0; i < ARRAY_SIZE(allow); ++i, reg += 16/(t/8)) { \ + if (!(select & (1 << i))) \ + continue; \ + p = msg; \ + for (j = 0; j < 0x10/(t/8); ++j) { \ + *p++ = ' '; \ + if (j == 8/(t/8)) \ + *p++ = ' '; \ + if (allow_reg_read(i, j, t)) \ + p += sprintf(p, format, reg[j]); \ + else \ + p += sprintf(p, "%s", xp); \ + } \ + dev_dbg(dev, "%s 0x%02X %s\n", prefix[i], i << 4, msg); \ + } \ +} + +#define CB710_READ_AND_DUMP_REGS_TEMPLATE(t) \ +static void cb710_read_and_dump_regs_##t(struct cb710_chip *chip, \ + unsigned select) \ +{ \ + u##t regs[CB710_REG_COUNT/sizeof(u##t)]; \ + \ + memset(®s, 0, sizeof(regs)); \ + cb710_read_regs_##t(chip->iobase, regs, select); \ + cb710_dump_regs_##t(cb710_chip_dev(chip), regs, select); \ +} + +#define CB710_REG_ACCESS_TEMPLATES(t) \ + CB710_READ_REGS_TEMPLATE(t) \ + CB710_DUMP_REGS_TEMPLATE(t) \ + CB710_READ_AND_DUMP_REGS_TEMPLATE(t) + +CB710_REG_ACCESS_TEMPLATES(8) +CB710_REG_ACCESS_TEMPLATES(16) +CB710_REG_ACCESS_TEMPLATES(32) + +void cb710_dump_regs(struct cb710_chip *chip, unsigned select) +{ + if (!(select & CB710_DUMP_REGS_MASK)) + select = CB710_DUMP_REGS_ALL; + if (!(select & CB710_DUMP_ACCESS_MASK)) + select |= CB710_DUMP_ACCESS_8; + + if (select & CB710_DUMP_ACCESS_32) + cb710_read_and_dump_regs_32(chip, select); + if (select & CB710_DUMP_ACCESS_16) + cb710_read_and_dump_regs_16(chip, select); + if (select & CB710_DUMP_ACCESS_8) + cb710_read_and_dump_regs_8(chip, select); +} +EXPORT_SYMBOL_GPL(cb710_dump_regs); + -- cgit v1.3.1