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/clocksource/mmio.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) create mode 100644 drivers/clocksource/mmio.c (limited to 'drivers/clocksource/mmio.c') diff --git a/drivers/clocksource/mmio.c b/drivers/clocksource/mmio.c new file mode 100644 index 000000000..0fee8edb8 --- /dev/null +++ b/drivers/clocksource/mmio.c @@ -0,0 +1,75 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Generic MMIO clocksource support + */ +#include +#include +#include +#include + +struct clocksource_mmio { + void __iomem *reg; + struct clocksource clksrc; +}; + +static inline struct clocksource_mmio *to_mmio_clksrc(struct clocksource *c) +{ + return container_of(c, struct clocksource_mmio, clksrc); +} + +u64 clocksource_mmio_readl_up(struct clocksource *c) +{ + return (u64)readl_relaxed(to_mmio_clksrc(c)->reg); +} +EXPORT_SYMBOL_GPL(clocksource_mmio_readl_up); + +u64 clocksource_mmio_readl_down(struct clocksource *c) +{ + return ~(u64)readl_relaxed(to_mmio_clksrc(c)->reg) & c->mask; +} +EXPORT_SYMBOL_GPL(clocksource_mmio_readl_down); + +u64 clocksource_mmio_readw_up(struct clocksource *c) +{ + return (u64)readw_relaxed(to_mmio_clksrc(c)->reg); +} +EXPORT_SYMBOL_GPL(clocksource_mmio_readw_up); + +u64 clocksource_mmio_readw_down(struct clocksource *c) +{ + return ~(u64)readw_relaxed(to_mmio_clksrc(c)->reg) & c->mask; +} +EXPORT_SYMBOL_GPL(clocksource_mmio_readw_down); + +/** + * clocksource_mmio_init - Initialize a simple mmio based clocksource + * @base: Virtual address of the clock readout register + * @name: Name of the clocksource + * @hz: Frequency of the clocksource in Hz + * @rating: Rating of the clocksource + * @bits: Number of valid bits + * @read: One of clocksource_mmio_read*() above + */ +int clocksource_mmio_init(void __iomem *base, const char *name, + unsigned long hz, int rating, unsigned bits, + u64 (*read)(struct clocksource *)) +{ + struct clocksource_mmio *cs; + + if (bits > 64 || bits < 16) + return -EINVAL; + + cs = kzalloc_obj(struct clocksource_mmio); + if (!cs) + return -ENOMEM; + + cs->reg = base; + cs->clksrc.name = name; + cs->clksrc.rating = rating; + cs->clksrc.read = read; + cs->clksrc.mask = CLOCKSOURCE_MASK(bits); + cs->clksrc.flags = CLOCK_SOURCE_IS_CONTINUOUS; + + return clocksource_register_hz(&cs->clksrc, hz); +} +EXPORT_SYMBOL_GPL(clocksource_mmio_init); -- cgit v1.3.1