1254263 - Add a pref to stop skipping paints

Status: RESOLVED FIXED

(Core :: Panning and Zooming, defect)

Description

[Kartikaya Gupta (email:[e-mail])]

We have some code that tries to avoid doing paints on the main thread if APZ is scrolling; it was added in bug 1187432. In general this is good, but if we have bugs where APZ doesn't update things properly then they can be made worse by this paint skipping. We should add a kill switch pref to disable the paint skipping in case we need it.

Comment 1

[Kartikaya Gupta (email:[e-mail])]

Attachment: MozReview Request: Bug 1254263 - Add a flag to allow disabling paint-skipping. r?mstange

Review commit: https://reviewboard.mozilla.org/r/38515/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/38515/

Comment 2

[Markus Stange [:mstange]]

Comment on attachment 8727584 [details]
MozReview Request: Bug 1254263 - Add a flag to allow disabling paint-skipping. r?mstange

https://reviewboard.mozilla.org/r/38515/#review35145

Comment 3

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/65f225f7d0db

Comment 4

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/65f225f7d0db

Comment 5

[Kartikaya Gupta (email:[e-mail])]

Comment on attachment 8727584 [details]
MozReview Request: Bug 1254263 - Add a flag to allow disabling paint-skipping. r?mstange

Approval Request Comment
[Feature/regressing bug #]: adds a pref to disable APZ paint skipping
[User impact if declined]: none really, but it's good to have a pref to disable this feature just in case
[Describe test coverage new/current, TreeHerder]: tested locally, been on m-c for a few days
[Risks and why]: low risk. just adds a pref to control some behaviour.
[String/UUID change made/needed]: none

Comment 6

[Ritu Kothari (:ritu) (Inactive, please n-i to RyanVM, jcristau, or pascal)]

Comment on attachment 8727584 [details]
MozReview Request: Bug 1254263 - Add a flag to allow disabling paint-skipping. r?mstange

new pref, tested locally, taking it.

Comment 7

[Liz Henry (:lizzard) (relman/hg->git project)]

Comment on attachment 8727584 [details]
MozReview Request: Bug 1254263 - Add a flag to allow disabling paint-skipping. r?mstange

Adds a pref for more control over APZ features, ok to uplift

Comment 8

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/releases/mozilla-aurora/rev/5ba3d463ebff

Comment 9

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

I'm hitting conflicts uplifting this to beta:

grafting 332450:5ba3d463ebff "Bug 1254263 - Add a flag to allow disabling paint-skipping. r=mstange a=ritu"
merging gfx/layers/apz/src/AsyncPanZoomController.cpp
merging gfx/thebes/gfxPrefs.h
merging layout/generic/nsGfxScrollFrame.cpp
merging layout/xul/nsSliderFrame.cpp
merging modules/libpref/init/all.js
warning: conflicts while merging gfx/layers/apz/src/AsyncPanZoomController.cpp! (edit, then use 'hg resolve --mark')
warning: conflicts while merging gfx/thebes/gfxPrefs.h! (edit, then use 'hg resolve --mark')
warning: conflicts while merging modules/libpref/init/all.js! (edit, then use 'hg resolve --mark')
abort: unresolved conflicts, can't continue


Can we get a rebased patch if this needs uplifting to beta?

Comment 10

[Kartikaya Gupta (email:[e-mail])]

Rebased and landed:

https://hg.mozilla.org/releases/mozilla-beta/rev/cd9a385c536c