Crate drmkit_display 

Display characterization and color handling.

What a connected display can do, and what has to happen to pixels before they reach it. Two halves that mostly do not talk to each other.

Finding the display

• ScanoutTarget — the connected output and the CRTC and primary plane that drive it, which is the pair everything downstream needs and the one thing crtcs().first() reliably gets wrong on real hardware.
• query_connector_modes — what each connector offers, with Probe deciding whether to ask the sink or trust the cache.
• ConnectorCapabilities and CrtcCapabilities — the properties this pipe actually exposes, so a caller writes what the driver has rather than what the spec allows.
• HotplugMonitor — the kernel’s own uevent stream, behind the hotplug feature.
• DriverProfile — device capabilities, probed and never inferred from the driver’s name.

Getting the pixels right

• ToneMapper — SDR to HDR and back, over a ToneMapCurve. Color maths has too many plausible readings for a paper derivation to be worth much, so its answers are diffed against the reference’s own, vector by vector.
• CrtcColorPipeline — the CRTC’s degamma, CTM and gamma stages. Each refuses on its own rather than the pipeline refusing whole, because partial pipelines are the common case: of 4,129 CRTCs surveyed, 848 have no color stage at all and three more shapes sit between that and the full three.
• HdrSourceMetadata and HdrMetadataCache — the CTA-861.3 blob a sink needs to switch into HDR, and the cache that stops it being rewritten every frame. Its green/blue/red primary ordering and tail padding are both invisible on screen and both change the bytes, so this is diffed against the reference too, over twelve vectors.
• edid — what the sink says about itself, behind the edid feature.

Features

edid is off by default: libdisplay-info-sys links a system library, and the cross lanes have no sysroot for it. Everything else here — the tone mapper and color curves that downstream crates want — builds without it.

Re-exports

pub use curves::ColorCtm;

pub use curves::ColorLut;

pub use hdr::HdrBlob;

pub use hdr::HdrMetadataBlob;

pub use hdr::HdrSourceMetadata;

pub use hdr::TransferFunction;

pub use hdr::hdr_metadata_hash;

pub use hdr::serialize_hdr_metadata;

pub use hdr_cache::HdrMetadataCache;

pub use scanout::CrtcChoice;

pub use scanout::ScanoutError;

pub use scanout::ScanoutTarget;

pub use scanout::crtc_for_connector;

pub use scanout::primary_plane_for_crtc;

pub use scanout::rank;

pub use scanout::rank_pick;

Modules

color

Color primaries, independent of where they came from.

curves

Transfer functions.

edid

What a connected display says about itself.

hdr

Source-side HDR static metadata, and the property blob that carries it.

hdr_cache

Per-CRTC cache of the HDR_OUTPUT_METADATA blob.

scanout

Finding something to put a picture on.

Structs

ConnectorCapabilities

What one connector’s color properties can be set to.

ConnectorModes

One connector and the modes it advertises.

CrtcCapabilities

What one CRTC’s color pipeline can be asked to do.

CrtcColorPipeline

The color pipeline of one CRTC.

DriverProfile

A device’s capabilities.

HotplugEvent

One connector changing.

HotplugMonitor

A pollable watch on DRM hotplug.

MaxBpc

The max bpc range, and where it currently sits.

PrimeCaps

What DRM_CAP_PRIME’s bitmask says.

ToneMapper

A configured tone-mapping transform.

Enums

BroadcastRgb

A connector’s Broadcast RGB entries.

Colorspace

A connector’s Colorspace entries, by the kernel’s names.

Direction

Which transform a mapper performs.

PanelSelfRefresh

Whether a connected panel might hold its image without a flip.

PipelineError

What can go wrong programming the pipeline.

Probe

Whether to make the kernel ask the display again.

Source

Where the uevents are read from.

Stage

Which stage a call was about.

ToneMapCurve

The curve applied in linear light when compressing HDR into SDR.

Constants

LUT_SIZE

Entries in each lookup table: 1024 buckets plus one sentinel.

Functions

connector_type_self_refreshes

Whether a connector type can hold its image without a flip.

decode_prime_caps

Decode the DRM_CAP_PRIME bitmask.

query_connector_modes

Every connector on the device, with its modes.