Struct FrameEconomy 

pub struct FrameEconomy { /* private fields */ }

The per-frame present decision, and what it has decided so far.

The point of it

The win is the skip. When nothing has changed since the last commit, the present loop issues no atomic commit at all — no flip, no reprogram. That is power saved on every panel, and on a panel capable of self-refresh it is what lets the panel stay there.

So the skip is unconditional and consults no PSR capability. Not flipping is a win whether or not the panel can self-refresh, and gating it on a capability would mean burning power on the panels that advertise nothing — which is most of them.

Threading

Not synchronized: one present loop owns it, the same one that owns the BufferRing.

Implementations

impl FrameEconomy

pub const fn new() -> Self

A fresh economy, whose first decision is always a full commit.

pub const fn decide( &mut self, content_changed: bool, damage_available: bool, ) -> FrameAction

Decide this frame.

content_changed is whether a layer produced a new frame or the scene mutated since the last committed one. damage_available is whether the producer supplied a bounded damage rectangle set, so a damaged commit is possible at all.

The first decision after construction or force_full is always FrameAction::CommitFull: the scanout buffer’s contents are otherwise undefined, or a modeset has just discarded them.

pub const fn force_full(&mut self)

Make the next decision a full commit.

For after a modeset, a mode change or a rebind — anything that leaves the previous scanout contents no longer applying, so damage against them would repaint the wrong difference. One-shot: it applies to the next decision and then clears.

pub const fn committed(&self) -> u64

How many frames have been committed.

pub const fn skipped(&self) -> u64

How many frames have been skipped — the ones that cost nothing.

Trait Implementations

impl Debug for FrameEconomy

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

Formats the value using the given formatter.

impl Default for FrameEconomy

fn default() -> Self

The same as new: the first decision commits in full.