1819154 - Make paused compositors respond to requestAnimationFrame at some cadence.

Status: NEW

(Core :: Layout, defect, P3)

Description

[Brad Werth [:bradwerth]]

Currently, if the compositor is paused, web content calling requestAnimationFrame will never receive a callback. Bug 1768495 makes this issue more likely because the compositor will be paused in fully-occluded windows. Because web content may rely upon RAF firing eventually we should make RAF wake-up the compositor at some cadence.

Comment 1

[Emilio Cobos Álvarez (:emilio)]

Is it really never-fired? Or is it fired at throttled-frame-rate? I'd expect the later but...

Comment 2

[Brad Werth [:bradwerth]]

(In reply to Emilio Cobos Álvarez (:emilio) from comment #1)

Is it really never-fired? Or is it fired at throttled-frame-rate? I'd expect the later but...

I think never fired. The failure in Bug 1768495 on test 1478035.html showed no callback from requestAnimationFrame for 3.5 minutes before the test timed out.

Comment 3

[Brad Werth [:bradwerth]]

The MozAfterPaint event may also not be fired when the compositor is paused.

Comment 4

[Brad Werth [:bradwerth]]

"animationend" events are also not sent.

Comment 5

[Timothy Nikkel (:tnikkel)]

(In reply to Brad Werth [:bradwerth] from comment #2)

(In reply to Emilio Cobos Álvarez (:emilio) from comment #1)

Is it really never-fired? Or is it fired at throttled-frame-rate? I'd expect the later but...

I think never fired. The failure in Bug 1768495 on test 1478035.html showed no callback from requestAnimationFrame for 3.5 minutes before the test timed out.

The tick happens, but we will just keep hitting this early return

https://searchfox.org/mozilla-central/rev/236aff736d092e69cdf9638a026be326ecec7e07/layout/base/nsRefreshDriver.cpp#2574

because we are waiting for a paint aka waiting for the compositor to notify us of a completed transaction.