1825419 - WebGPU CTS fails to initialize DirectX debug layer(s)

Status: NEW

(Core :: Graphics: WebGPU, defect, P2)

Description

[Erich Gubler [:ErichDonGubler]]

WebGPU CTS currently fails to initialize debugging layers for its dx12 back end. This is a potentially significant problem for debugging failures in Windows builds; clear diagnostics are often key to resolving impactful issues such as portability hazards and undefined behavior. We'd like to ensure that this runs correctly in at least our CI runners on Windows machines.

Steps to reproduce

1. Configure WebGPU to run on Firefox. ATOW, this means setting the dom.webgpu.enabled pref. to true, but this may not be necessary soon.

2. Ensure that the dom.webgpu.wgpu-backend pref. is set to dx12.

3. Ensure that the RUST_LOG environment variable is set to at least wgpu_hal=info.

4. Invoke Firefox in a context where WebGPU will be exercised, and observe log messages like the following:

    [WARN  wgpu_hal::dx12::instance] Unable to enable D3D12 debug interface: 0x887A002D
    [WARN  wgpu_hal::auxil::dxgi::factory] Unable to enable DXGI debug interface: 0x887A002D
   

To give a concrete example of the above, you can apply the following patch, which sets the correct prefs. for WebGPU's current CTS tests:

--- a/testing/web-platform/mozilla/meta/webgpu/__dir__.ini
+++ b/testing/web-platform/mozilla/meta/webgpu/__dir__.ini
@@ -1,1 +1,2 @@
-prefs: [dom.webgpu.enabled:true]
+prefs: [dom.webgpu.enabled:true,
+        dom.webgpu.wgpu-backend:dx12]

…and run one of the reftests:

RUST_LOG=wgpu_hal=info ./mach wpt /_mozilla/webgpu/webgpu/web_platform/reftests/canvas_colorspace_rgba8unorm.https.html

Observations

This issue has been observed only on Windows 11 until now. It's possible that other versions of Windows also have this issue, and we haven't witnessed it and recorded it here yet.

Comment 1

[Erich Gubler [:ErichDonGubler]]

Motivating context from :jimb: https://matrix.to/#/!wbEUPKmXGxodKqLlZL:mozilla.org/$oqIsi42MRflza9H7m6WpkfRsGCTgdPTPi1HFlmb7xGs?via=mozilla.org&via=matrix.org&via=igalia.com

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1720941

Comment 3

[Erich Gubler [:ErichDonGubler]]

This bug may be affected (positively) by wgpu#3987, where I avoid several apparent null states for some COM pointers (including debug layer initialization specifically). EDIT: Probably not the case, actually.

Comment 4

[Erich Gubler [:ErichDonGubler]]

The entry in DXGI_ERROR for the error code I listed in the description:

DXGI_ERROR_SDK_COMPONENT_MISSING

0x887A002D

The operation depends on an SDK component that is missing or mismatched.