2059441 - Avoid enabling certain mac driver bug workarounds on Metal ANGLE

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, task)

Description

[Jamie Nicol [:jnicol]]

On macOS we have a few different driver bug workarounds in webrender:

• Blocking texture storage due to lack of BGRA support
• Using a large PBO stride alignment due to AMD bugs
• Only uploading from PBO offsets of 0, due to AMD bugs

The latter two of these only apply to AMD GPUs, but we unconditionally apply the workaround anyway because it's possible that the device is created on another GPU and then migrated to an AMD GPU at runtime.

These bugs presumably don't apply to Metal ANGLE -- I did a quick sanity check on an AMD device, but didn't test in depth. Additionally, Metal ANGLE does not support GPU migration, so there's no need to pessimistically apply the workaround. (Currently we block Metal ANGLE on devices with multiple GPUs, and when we eventually support such devices we'll need to do something like recreating the renderer rather than just migrating the GL context.)

Avoiding the PBO offset limitation looks like it will be especially valuable from the profiles I've looked at, as it will allow us to use the same PBO for multiple uploads, reducing the number of required allocations.

Comment 1

[Jamie Nicol [:jnicol]]

Attachment: Bug 2059441 - Disable some macOS driver bug workarounds on Metal ANGLE. r?#gfx-reviewers

Metal ANGLE does not appear to be affected by these driver bugs. And
since it does not support GPU migration we don't need to
pessimistically apply them even on unaffected GPUs.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/bea8db6aa32d
https://hg.mozilla.org/integration/autoland/rev/a7617b22387d
Disable some macOS driver bug workarounds on Metal ANGLE. r=gfx-reviewers,nical

Comment 3

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/a7617b22387d