1285937 - WebGL canvas "Disallowing antialiased backbuffers due to blacklisting." error

Status: RESOLVED DUPLICATE of bug 757642

(Core :: Graphics: CanvasWebGL, defect, P3)

Description

[Jukka Jylänki]

On a Mac Pro (Late 2013) OS X 10.11.5 workstation with 3.5 GHz 6-Core Intel Xeon E5 and AMD FirePro D500 3072 MB, WebGL content receives an error

Error: WebGL: Disallowing antialiased backbuffers due to blacklisting.

It would be good practice to reference to the causing bugzilla bug entry in these kind of errors, so that developers will be able to do an educated guess as to what part of their setup to improve (do I need a new GPU or is an OS X version update enough?) and what caused the creation of the blacklist entry. If the bugzilla # looks messy to include in the web console, perhaps it could be printed in about:support Graphics section instead.

about:support for this system says

Graphics
Asynchronous Pan/Zoom	none
Device ID	0x679e
GPU Accelerated Windows	1/1 OpenGL (OMTC)
Supports Hardware H264 Decoding	No
Vendor ID	0x1002
WebGL Renderer	ATI Technologies Inc. -- AMD Radeon HD - FirePro D500 OpenGL Engine
windowLayerManagerRemote	true
AzureCanvasAccelerated	1
AzureCanvasBackend	skia
AzureContentBackend	quartz
AzureFallbackCanvasBackend	none


Comparing the output of e.g. http://learningwebgl.com/lessons/lesson02/index.html in Safari 9.1.1 and Firefox 47 or Nightly, Safari does get antialiasing but Firefox does not.

Is there a GPU driver bug that means that Safari is unsecure since it enabled antialiasing? Or does this error message refer to an old Firefox blacklist item that is no longer relevant?

Comment 1

[Jukka Jylänki]

Attachment: Create nonantialiased GL context

Actually, inspecting further, it looks like the error "Error: WebGL: Disallowing antialiased backbuffers due to blacklisting." is unconditionally printed even when user does not request antialiasing.

See the attached test case that creates a GL context without antialiasing, using 

	var gl = canvas.getContext('webgl', { antialias: false });

but the error is still posted to console on this AMD FirePro GPU.

Comment 2

[Jukka Jylänki]

Hey, there was that recent work to explicitly report the reasons that caused blacklisting. We're still seeing this in the wild, and I'm curious as to why AMD GPU on OS X does not get antialiasing. The error message that is posted in comment 1 only gives an opaque

"Error: WebGL: Disallowing antialiased backbuffers due to blacklisting."

and about:support does not have any mentions about this.

1) Which bugzilla bug number introduced this blacklist?

2) Why was AMD OS X GPUs blacklisted for antialiasing?

3) Could that error message be improved to say

"Error: WebGL: Disallowing antialiased backbuffers due to blacklisting. See https://bugzilla.mozilla.org/show_bug.cgi?id=bugnumberthatintroducedthisblacklist"

4) Was there a pref that one can use to force-ignore blacklists? I vaguely recall something along these lines, but can't quite spot what it was.

It would be good to have an explicitly documented trail provided by Firefox in cases like this so that it's easy to investigate what the circumstances are regarding workarounds like this that have put in place. That would at least give some chance to our community contributors to be able to provide back data like "hey, this has started to work now on OS X version xyz or GL driver version abc.", because it's unlikely that we would routinely triage through these periodically.

Comment 3

[Jukka Jylänki]

Bisected this blacklist to have occurred somewhere between

 7:19.56 INFO: Got as far as we can go bisecting nightlies...
 7:19.56 INFO: Last good revision: 3be45b58fc47 (2014-08-28)
 7:19.56 INFO: First bad revision: d697d649c765 (2014-08-29)
 7:19.56 INFO: Pushlog:
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=3be45b58fc47&tochange=d697d649c765

but not immediately sure which commit caused it.

Comment 4

[Jeff Muizelaar [:jrmuizel]]

(In reply to Jukka Jylänki from comment #2)
> Hey, there was that recent work to explicitly report the reasons that caused
> blacklisting. We're still seeing this in the wild, and I'm curious as to why
> AMD GPU on OS X does not get antialiasing. The error message that is posted
> in comment 1 only gives an opaque
> 
> "Error: WebGL: Disallowing antialiased backbuffers due to blacklisting."
> 
> and about:support does not have any mentions about this.
> 
> 1) Which bugzilla bug number introduced this blacklist?

Bug 695912.

> 2) Why was AMD OS X GPUs blacklisted for antialiasing?

The bug doesn't say. Maybe jgilbert knows. He reviewed it. I think we can probably loosen this blacklisting.

> 3) Could that error message be improved to say
> 
> "Error: WebGL: Disallowing antialiased backbuffers due to blacklisting. See
> https://bugzilla.mozilla.org/show_bug.
> cgi?id=bugnumberthatintroducedthisblacklist"

Yes.

> 4) Was there a pref that one can use to force-ignore blacklists? I vaguely
> recall something along these lines, but can't quite spot what it was.

You can force individual things. I don't believe we have a pref to force-ignore blacklisting in general.


> It would be good to have an explicitly documented trail provided by Firefox
> in cases like this so that it's easy to investigate what the circumstances
> are regarding workarounds like this that have put in place. That would at
> least give some chance to our community contributors to be able to provide
> back data like "hey, this has started to work now on OS X version xyz or GL
> driver version abc.", because it's unlikely that we would routinely triage
> through these periodically.


I agree this would be good.

Comment 5

[Stuart]

This warning is appearing even when anti-aliasing isn't requested, e.g. on https://get.webgl.org/

Either only showing it when anti-aliasing is specifically requested, or linking to this bug would be good.