Crash when enabling async compute

Development Rendering
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1

I had cherry-picked the following commits into our 5.6.1 branch in the hopes that this makes async compute safe to use in 5.6:

https://github.com/EpicGames/UnrealEngine/commit/ab1083e4d04765e4daf32c68f807d10b7cec23ad

https://github.com/EpicGames/UnrealEngine/commit/e23bf8c26bb2ae9dc5240fa1c001a71b35ac34ae

I’m crashing on a resource transition issue. When I run with “-RHIValidation -d3ddebug -norhithread -forcerhibypass” I get the following error:

RHI validation failed for resource: “TextureRenderTarget2D_0” (0x000001F452EA9A40) (Whole Resource):

--------------------------------------------------------------------

   RHI Resource Transition Validation Error

--------------------------------------------------------------------

Attempted to access resource “TextureRenderTarget2D_0” (0x000001F452EA9A40) (Whole Resource) from a hardware unit it is not currently accessible from. A resource transition is required.

--- Allowed access states for this resource are: SRVCompute|SRVGraphicsPixel|SRVGraphicsNonPixel

--- Required access states are: SRVCompute

--- Allowed pipelines for this resource are: Graphics

--- Required pipelines are: AsyncCompute

--------------------------------------------------------------------

Interestingly, when I add -rdgimmediate the problem goes away. This makes me wonder if the RDG pass itself is missing some kind of markup that is necessary to enumerate transitions on this resource properly.

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2

Steps to Reproduce
Run editor w/ async compute enabled. We disabled it as of 5.5 and just tried to turn it back on in our 5.6.1 project.

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3

Hi there,

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Thanks for the report.

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Based on the report, it appears that RDG may not be aware that the pass requires the resource TextureRenderTarget2D_0 on the async compute pipeline.

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I could not reproduce the issue on my end. The crash may be related to a specific project config or asset setup in this case.

If possible, could you please provide detailed reproduction steps or a minimal repro project, this would greatly assist us in further investigating and identifying the root cause of the issue.

Best regards,

Henry Liu

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