779580 - Blacklist WebGL MSAA on Intel driver on Mesa 8.1, as it was lying about GL_MAX_SAMPLES

Status: RESOLVED FIXED

(Core :: Graphics: CanvasWebGL, defect)

Description

[Benoit Jacob [:bjacob] (mostly away)]

As discussed on the mesa-dev list, the Intel Mesa driver (as of Mesa 8.0) wrongly returns GL_MAX_SAMPLES>0 even though the correct value is 0 (does not support msaa FBOs).

That's causing a test failure in https://www.khronos.org/registry/webgl/conformance-suites/1.0.1/conformance/context/context-attributes-alpha-depth-stencil-antialias.html which is actually the very last 1.0.1 test failure.

Setting webgl.msaa-level=0 does now give a full pass, and as we already have a full pass on NVIDIA 302.17, it's worth doing a little workaround to get that second full pass we need to claim conformance on Linux.

So let's assume that Intel Mesa never supports msaa FBOs, until further notice. I asked mesa devs if it's already fixed in trunk; if it is, we'll do a version check instead.

Comment 1

[Benoit Jacob [:bjacob] (mostly away)]

Attachment: block msaa on Intel

Comment 2

[Benoit Jacob [:bjacob] (mostly away)]

Attachment: block msaa on Intel on Mesa < 8.1

Comment 3

[Benoit Jacob [:bjacob] (mostly away)]

Ken from the mesa-dev list confirmed that this is fixed in versions >= 8.1.0.

Comment 4

[Benoit Jacob [:bjacob] (mostly away)]

http://hg.mozilla.org/integration/mozilla-inbound/rev/90495de76df0

Comment 5

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/90495de76df0