1175212 - "Use hardware acceleration when available" should also control WebGL acceleration?

Status: NEW

(Core :: Graphics, defect)

Description

[Milan Sreckovic [:milan] (needinfo for best results)]

+++ This bug was initially created as a clone of Bug #1171682 +++

Currently, the "Preferences->Advanced->Use hardware acceleration when available" does not consistently apply to all aspects of acceleration.

When turned off, we get non-accelerated OMT compositor.  This is good.
On Windows we also switch to unaccelerated content and canvas.  This is also good.

However, we still allow WebGL to be accelerated, either through ANGLE or OpenGL, depending on the platform.

layers.acceleration.disabled controls the compositor acceleration.  webgl.disabled controls full WebGL, but we may eventually want a software WebGL when hardware acceleration is disabled.

Or we can leave things as they are - the main thing is the intent of the "Use hardware acceleration when available".  If it is just meant to control the content+canvas+compositor acceleration, because we have more bugs in there than in WebGL, then perhaps we just leave things as the currently are.

So, our options appear to be:

1. Leave things as they are today.  "Use hardware acceleration when available" applies to content+canvas+compositor, but not to WebGL.

2. Add WebGL "acceleration control" to the same UI control; for the cases where we do not have software backed WebGL, that would effectively disable it.

3. We can come up with #3 and #4, but things start getting complicated.

Comment 1

[Milan Sreckovic [:milan] (needinfo for best results)]

Our documentation separates WebGL and this preference, so we are consistent if people read the documentation.  Perhaps it is enough to communicate to everybody for triage purposes that the graphics card could be used unless we also disable WebGL through about:config.

Comment 2

[Benoit Girard (:BenWa)]

I think the question we care about here: When someone is hitting a layers acceleration issues, say a scrolling performance regression which I see often on reddit or perhaps a correctness/stability issue, those users will flip that setting. Do we also think that if they're experiencing layers acceleration issue that they will face WebGL issue?

From my discussion from bjacob this was not simply yes. A lot of the issues we hit deal with texture sharing and non usual things we do that drivers don't handle well. Typically WebGL still works fine for those users and doing #2 would drop our WebGL success state.

For now I'm incline to vote for #1 + maybe reword the string. But I don't really feel strongly about this.

Comment 3

[Milan Sreckovic [:milan] (needinfo for best results)]

Right - safe mode is really the one that we really wanted, and that got taken care of in bug 1171682.  I'm not rushing to do anything about this bug.

Comment 4

[Kelsey Gilbert [:jgilbert]]

I say #1, but actually move canvas over to the WebGL side of things.

As far as I'm aware, there are two main usecases for unticking the "use hardware accel" checkbox:
A) Unresolved layers issues (lagginess, corruption, etc.)
B) Text rastering preferences (hinting, etc)

(A) relates to hardware accel layers
(B) relates to content rendering

I think that if we want a checkbox for 'prefer software canvas', we should add it explicitly and separately.
Generally, canvas issues do not interfere with web browsing, whereas layers issues and content rendering issues will hurt browsing a lot.


For the purpose of this bug itself, I move we mark WONTFIX.