Is UPDATE_AFTER_BIND suppose to only be updated before pending state

[spencer-lunarg]

This VU make is sound like if you use UPDATE_AFTER_BIND (without UPDATE_UNUSED_WHILE_PENDING) you are able to still call vkUpdateDescriptorSets while the command buffer is pending

I assume this should really be

• If in executable state, either UPDATE_AFTER_BIND or UPDATE_UNUSED_WHILE_PENDING must be set
• If in pending state, UPDATE_UNUSED_WHILE_PENDING must be set

[spencer-lunarg]

WG 08/26/26 - Agreed the language is misleading and my assumption above is correct. Will go and cleanup the VU and surrounding language to make this clear

[spencer-lunarg]

closing with KhronosGroup/Vulkan-ValidationLayers#12943

decided not a spec issue and the validation layer message could do a better job explaining why both are needed actually

[AlexRouSg]

the new message kinda sounds like you need both to update only unused with pending command buffers,
or did I misread the trigger for the message?

[spencer-lunarg]

you do...

Basically the idea is the rules also depend a bit if you are updating statically indexed vs dynamically indexed

I was told if you are already setting UPDATE_UNUSED_WHILE_PENDING, adding UPDATE_AFTER_BIND should not be any issue, it was the other way around some drivers needed to know the flag set

In theory, you could just use UPDATE_UNUSED_WHILE_PENDING, but in practice, was told to set UPDATE_AFTER_BIND

[spencer-lunarg]

the "in theory" part is only if all your indexes into the descriptor array are fully static such that it can be determined at shader compile time you would not touch the other descriptors

I will also say Descriptor Heap also solves this all by just letting you have full access to the descriptor memory

[AlexRouSg]

if UWP in theory only works for statically unused, I feel like that qualifies for some spec clarification since there is no hint to it.
Maybe explicitly mention the interaction when both are defined allowing updates to dynamically unused but I am unable to come up with wording that makes sense.