Struct ModifierProbeCache 

pub struct ModifierProbeCache { /* private fields */ }

Memoizes atomic TEST_ONLY verdicts.

An IN_FORMATS that advertises a modifier the hardware cannot actually program — historically some pre-6.16 MediaTek OVL instances — then costs one probe rather than one glitch per frame.

Backed by a linear scan: the entry count is bounded by crtcs * planes * formats actually exercised, which is small, and a scan beats hashing at this size.

use drmkit_fmt::{Modifier, ModifierProbeCache, Verdict, fourcc};

let mut cache = ModifierProbeCache::new();
assert_eq!(cache.lookup(1, 31, fourcc::XRGB8888, Modifier::LINEAR), Verdict::Unknown);

cache.record(1, 31, fourcc::XRGB8888, Modifier::LINEAR, true);
assert_eq!(cache.lookup(1, 31, fourcc::XRGB8888, Modifier::LINEAR), Verdict::Ok);

// A modeset or hotplug invalidates everything cached for that plane.
cache.invalidate_plane(31);
assert_eq!(cache.lookup(1, 31, fourcc::XRGB8888, Modifier::LINEAR), Verdict::Unknown);

Implementations

impl ModifierProbeCache

pub const fn new() -> Self

An empty cache.

pub fn lookup( &self, crtc: u32, plane: u32, fourcc: u32, modifier: Modifier, ) -> Verdict

The cached verdict, or Verdict::Unknown.

pub fn record( &mut self, crtc: u32, plane: u32, fourcc: u32, modifier: Modifier, ok: bool, )

Record a probe outcome, replacing any previous verdict for the tuple.

pub fn invalidate_plane(&mut self, plane: u32)

Drop every verdict for a plane. Call on hotplug or modeset, after which a previously rejected modifier may well be accepted.

pub fn len(&self) -> usize

Number of cached verdicts.

pub fn is_empty(&self) -> bool

Whether nothing is cached.

Trait Implementations

impl Clone for ModifierProbeCache

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ModifierProbeCache

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ModifierProbeCache

fn default() -> Self

Returns the “default value” for a type.