Intent to Ship: WebGPU: GPUAdapterInfo isFallbackAdapter attribute

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François Beaufort

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Mar 24, 2025, 7:13:11 AM (11 days ago) Mar 24
to blink-dev

Contact emails

fbea...@google.com

Explainer

The GPUAdapter isFallbackAdapter boolean attribute currently shipped in Chrome browser only does not allow libraries that take user-provided GPUDevice objects from accessing this information through the adapterInfo attribute on GPUDevice. Adding a GPUAdapterInfo isFallbackAdapter boolean attribute solves this problem.


Note that GPUAdapter isFallbackAdapter usage is being measured to determine if it can be deprecated and removed, as Chrome has not yet shipped support for fallback adapters.

https://github.com/gpuweb/gpuweb/pull/5099

Specification

https://gpuweb.github.io/gpuweb/#dom-gpuadapterinfo-isfallbackadapter

Summary

Functionality added to the WebGPU spec after its first shipment in a browser. The GPUAdapterInfo isFallbackAdapter boolean attribute indicates if an adapter has significant performance limitations in return for wider compatibility, more predictable behavior, and/or improved privacy. Note that a fallback adapter may not be present on all systems.


Blink component

Blink>WebGPU

TAG review

None

TAG review status

Not applicable

Risks



Interoperability and Compatibility

This feature has not yet been implemented in any browser. It has been approved by the GPU for the Web Community Group, with representatives from Chrome, Firefox, and Safari. See minutes at https://github.com/gpuweb/gpuweb/wiki/GPU-Web-2025-03-05#move-isfallbackadapter-into-gpuadapterinfo-4971 and https://github.com/gpuweb/gpuweb/pull/5099#issuecomment-2737426600


Gecko: No signal Mozilla members have requested during weekly standardization meetings that we don't file standard positions anymore as we reached Candidate Recommendation (CR) status.

WebKit: Closed Without a Position (https://github.com/WebKit/standards-positions/issues/294#issuecomment-1877411933)

Web developers: Positive (https://github.com/gpuweb/gpuweb/issues/4971)

Other signals:

WebView application risks

Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?

None



Debuggability

None



Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, ChromeOS, Android, and Android WebView)?

No

All platforms will eventually have support. Will immediately be available on Android, Android WebView, ChromeOS, Mac, and Windows, since those platforms already support WebGPU. Linux is planned to have WebGPU support in the future, so this feature will become available when WebGPU does.



Is this feature fully tested by web-platform-tests?

Yes

WebGPU/WGSL have a conformance test suite (https://github.com/gpuweb/cts) that is regularly pulled into Chromium and part of the testing of Dawn/Tint in Chromium. While the CTS can be embedded in WPT, the WebGPU team opted to keep it separate in Chromium testing to use a customized harness for robustness and performance. All the tests about this feature in WebGPU CTS can be found at https://github.com/gpuweb/cts/issues/2356



Flag name on about://flags

Experimental Web Platform Features

Finch feature name

WebGPUAdapterInfoIsFallbackAdapter

Requires code in //chrome?

False

Tracking bug

https://issues.chromium.org/issues/403172841

Estimated milestones

No milestones specified



Anticipated spec changes

Open questions about a feature may be a source of future web compat or interop issues. Please list open issues (e.g. links to known github issues in the project for the feature specification) whose resolution may introduce web compat/interop risk (e.g., changing to naming or structure of the API in a non-backward-compatible way).

None

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/5188955424948224?gate=5167533973569536

This intent message was generated by Chrome Platform Status.

Yoav Weiss (@Shopify)

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Mar 27, 2025, 2:43:16 AM (9 days ago) Mar 27
to blink-dev, François Beaufort
LGTM1

TAMURA, Kent

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Mar 28, 2025, 2:44:51 AM (8 days ago) Mar 28
to blink-dev, François Beaufort, Yoav Weiss (@Shopify)
LGTM2


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TAMURA Kent
Software Engineer, Google


Mike Taylor

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Mar 28, 2025, 5:57:08 AM (8 days ago) Mar 28
to TAMURA, Kent, blink-dev, François Beaufort, Yoav Weiss (@Shopify)

LGTM3

For the history books, do we have this captured somewhere like meeting minutes?

Corentin Wallez

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Mar 31, 2025, 1:45:01 AM (5 days ago) Mar 31
to blink-dev, Mike Taylor, Yoav Weiss (@Shopify), TAMURA, Kent, François Beaufort
On Friday, March 28, 2025 at 1:57:08 PM UTC+1 Mike Taylor wrote:

LGTM3

On 3/28/25 5:44 AM, TAMURA, Kent wrote:
LGTM2


On Thu, Mar 27, 2025 at 6:43 PM Yoav Weiss (@Shopify) <yoav...@chromium.org> wrote:
LGTM1

On Monday, March 24, 2025 at 10:13:11 AM UTC-4 François Beaufort wrote:
Contact emails fbea...@google.com

 Explainer The GPUAdapter isFallbackAdapter boolean attribute currently shipped in Chrome browser only does not allow libraries that take user-provided GPUDevice objects from accessing this information through the adapterInfo attribute on GPUDevice. Adding a GPUAdapterInfo isFallbackAdapter boolean attribute solves this problem.
Note that GPUAdapter isFallbackAdapter usage is being measured to determine if it can be deprecated and removed, as Chrome has not yet shipped support for fallback adapters.

https://github.com/gpuweb/gpuweb/pull/5099

 Specification https://gpuweb.github.io/gpuweb/#dom-gpuadapterinfo-isfallbackadapter

 Summary

Functionality added to the WebGPU spec after its first shipment in a browser. The GPUAdapterInfo isFallbackAdapter boolean attribute indicates if an adapter has significant performance limitations in return for wider compatibility, more predictable behavior, and/or improved privacy. Note that a fallback adapter may not be present on all systems.


 Blink component Blink>WebGPU

 TAG review None

 TAG review status Not applicable

 Risks


Interoperability and Compatibility

This feature has not yet been implemented in any browser. It has been approved by the GPU for the Web Community Group, with representatives from Chrome, Firefox, and Safari. See minutes at https://github.com/gpuweb/gpuweb/wiki/GPU-Web-2025-03-05#move-isfallbackadapter-into-gpuadapterinfo-4971 and https://github.com/gpuweb/gpuweb/pull/5099#issuecomment-2737426600


Gecko: No signal Mozilla members have requested during weekly standardization meetings that we don't file standard positions anymore as we reached Candidate Recommendation (CR) status.
For the history books, do we have this captured somewhere like meeting minutes?

Not sure if you are asking about this change specifically or in general. For this feature they oked in the meeting where we talked about it. For the general agreement, I can't find a public statement for this, though they mentioned that repeatedly in sync meetings. What's the process to actually get statement like that? Should our Web standard folks reach out to Mozilla's?

Mike Taylor

unread,
Mar 31, 2025, 9:04:29 AM (4 days ago) Mar 31
to Corentin Wallez, blink-dev, Yoav Weiss (@Shopify), TAMURA, Kent


On 3/31/25 4:44 AM, Corentin Wallez wrote:


On Friday, March 28, 2025 at 1:57:08 PM UTC+1 Mike Taylor wrote:

LGTM3

On 3/28/25 5:44 AM, TAMURA, Kent wrote:
LGTM2


On Thu, Mar 27, 2025 at 6:43 PM Yoav Weiss (@Shopify) <yoav...@chromium.org> wrote:
LGTM1

On Monday, March 24, 2025 at 10:13:11 AM UTC-4 François Beaufort wrote:
Contact emails fbea...@google.com

 Explainer The GPUAdapter isFallbackAdapter boolean attribute currently shipped in Chrome browser only does not allow libraries that take user-provided GPUDevice objects from accessing this information through the adapterInfo attribute on GPUDevice. Adding a GPUAdapterInfo isFallbackAdapter boolean attribute solves this problem.
Note that GPUAdapter isFallbackAdapter usage is being measured to determine if it can be deprecated and removed, as Chrome has not yet shipped support for fallback adapters.

https://github.com/gpuweb/gpuweb/pull/5099

 Specification https://gpuweb.github.io/gpuweb/#dom-gpuadapterinfo-isfallbackadapter

 Summary

Functionality added to the WebGPU spec after its first shipment in a browser. The GPUAdapterInfo isFallbackAdapter boolean attribute indicates if an adapter has significant performance limitations in return for wider compatibility, more predictable behavior, and/or improved privacy. Note that a fallback adapter may not be present on all systems.


 Blink component Blink>WebGPU

 TAG review None

 TAG review status Not applicable

 Risks


Interoperability and Compatibility

This feature has not yet been implemented in any browser. It has been approved by the GPU for the Web Community Group, with representatives from Chrome, Firefox, and Safari. See minutes at https://github.com/gpuweb/gpuweb/wiki/GPU-Web-2025-03-05#move-isfallbackadapter-into-gpuadapterinfo-4971 and https://github.com/gpuweb/gpuweb/pull/5099#issuecomment-2737426600


Gecko: No signal Mozilla members have requested during weekly standardization meetings that we don't file standard positions anymore as we reached Candidate Recommendation (CR) status.
For the history books, do we have this captured somewhere like meeting minutes?

Not sure if you are asking about this change specifically or in general. For this feature they oked in the meeting where we talked about it. For the general agreement, I can't find a public statement for this, though they mentioned that repeatedly in sync meetings. What's the process to actually get statement like that? Should our Web standard folks reach out to Mozilla's?

Thanks for the pointer!

A simple way would be to file a Mozilla standards position and have someone say as much in a comment - then you could link to that similar to https://github.com/WebKit/standards-positions/issues/294#issuecomment-1877411933. If folks are in sync meetings with Mozilla folks, you could also ask them what they prefer (or they could even reply to this thread).

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