1118322 - Screen Tearing on Windows Nightly

Status: RESOLVED FIXED

(Core :: Graphics: Layers, defect)

Description

[Benoit Girard (:BenWa)]

I'm seeing screen tearing on nightly win7. I will narrow down the graphics feature responsible shortly.

[Tracking Requested - why for this release]:
Tearing regressions should be blocked on or explicitly accepted.

Comment 1

[Bas Schouten (:bas.schouten)]

Attachment: Block explicitly for vblank when using WARP.

I wonder if in addition to this we should set BufferCount to 2 in order to only block when we're getting ahead of the compositor. But let's see how this goes first.

Comment 2

[Jeff Muizelaar [:jrmuizel]]

Comment on attachment 8546059 [details] [diff] [review]
Block explicitly for vblank when using WARP.

Review of attachment 8546059 [details] [diff] [review]:
-----------------------------------------------------------------

::: gfx/layers/d3d11/CompositorD3D11.cpp
@@ +1114,5 @@
> +  if (gfxWindowsPlatform::GetPlatform()->IsUsingWARP()) {
> +    // When we're using WARP we cannot present immediately as it causes us
> +    // to tear when rendering.
> +    presentInterval = 1;
> +  }

It is not clear to me why we only want to do this with WARP. Shouldn't we do this everywhere?

Comment 3

[Lawrence Mandel [:lmandel] (use needinfo)]

Does this impact Beta 36?

Comment 4

[Bas Schouten (:bas.schouten)]

(In reply to Jeff Muizelaar [:jrmuizel] from comment #2)
> Comment on attachment 8546059 [details] [diff] [review]
> Block explicitly for vblank when using WARP.
> 
> Review of attachment 8546059 [details] [diff] [review]:
> -----------------------------------------------------------------
> 
> ::: gfx/layers/d3d11/CompositorD3D11.cpp
> @@ +1114,5 @@
> > +  if (gfxWindowsPlatform::GetPlatform()->IsUsingWARP()) {
> > +    // When we're using WARP we cannot present immediately as it causes us
> > +    // to tear when rendering.
> > +    presentInterval = 1;
> > +  }
> 
> It is not clear to me why we only want to do this with WARP. Shouldn't we do
> this everywhere?

It appears when not using WARP the DWM takes care of not tearing for us, how I don't know exactly, but it seemed like a waste to introduce an extra frame of latency when there's no need for that.

Comment 5

[Bas Schouten (:bas.schouten)]

(In reply to Lawrence Mandel [:lmandel] (use needinfo) from comment #3)
> Does this impact Beta 36?

It does not.

Comment 6

[Jeff Muizelaar [:jrmuizel]]

Comment on attachment 8546059 [details] [diff] [review]
Block explicitly for vblank when using WARP.

Review of attachment 8546059 [details] [diff] [review]:
-----------------------------------------------------------------

It would be nice to add a comment that contains your "It appears when not using WARP the DWM takes care of not tearing for us, how I don't know exactly, but it seemed like a waste to introduce an extra frame of latency when there's no need for that."

Comment 7

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/9105c55dbaee

Comment 8

[Lawrence Mandel [:lmandel] (use needinfo)]

Bas - 37 is affected. Is this suitable for uplift? If so, can you get a request in this week before 37 merges to Beta?

Comment 9

[Bas Schouten (:bas.schouten)]

Comment on attachment 8546059 [details] [diff] [review]
Block explicitly for vblank when using WARP.

Approval Request Comment
[Feature/regressing bug #]: 1102499
[User impact if declined]: Tearing when GPU is blacklisted
[Describe test coverage new/current, TreeHerder]: Extensive nightly coverage
[Risks and why]: Very low, at the very worst 1 frame of additional latency
[String/UUID change made/needed]: None

Comment 10

[Lawrence Mandel [:lmandel] (use needinfo)]

Comment on attachment 8546059 [details] [diff] [review]
Block explicitly for vblank when using WARP.

Aurora+

Comment 11

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-aurora/rev/dca9e009cc21