vkEnumerateInstanceExtensionProperties cannot be called from CreateInstance in a layer about vulkan-loader HOT 8 CLOSED

Comment by MarkY-LunarG (MIGRATED)
Friday Sep 08, 2017 at 14:52 GMT

This is currently "as designed". The original intent was this information was queried by the desktop loader from the layer JSON files. However, we are investigating the usefulness of this.

from vulkan-loader.

Comment by Themaister (MIGRATED)
Friday Sep 08, 2017 at 14:56 GMT

Similar for vkEnumerateDeviceExtensionProperties in CreateDevice.

from vulkan-loader.

Comment by Themaister (MIGRATED)
Friday Sep 08, 2017 at 14:56 GMT

The current workaround is dlsym(RTLD_DEFAULT, ...)

from vulkan-loader.

Comment by Themaister (MIGRATED)
Friday Sep 08, 2017 at 15:00 GMT

Actually, it's not ... vkEnumerateInstanceExtensions deadlocks in libvulkan.so. Probably some global lock is taken in vkCreateInstance and in vkEnumerateInstanceExtensions as well.

from vulkan-loader.

Comment by MarkY-LunarG (MIGRATED)
Friday Sep 08, 2017 at 15:01 GMT

I'm not sure why dlsym changes would make it work. The vkEnumerateInstanceExtensionProperties extension should be implemented by the loader and ICDs only and you shouldn't attempt to try to call the ICD function directly. We're looking into a more proper way to do this. However, I don't see why vkEnumerateDeviceExtensionProperties shouldn't work by default. I've assigned Lenny this issue, and he can look into more detail.

from vulkan-loader.

Comment by Themaister (MIGRATED)
Friday Sep 08, 2017 at 15:10 GMT

Yeah, dlsym(RTLD_DEFAULT) actually didn't work, so please disregard that.

What I tried was dlopen("libvulkan.so") directly, then call into vkEnumerateInstanceExtensionProperties, which deadlocked.

If there is something you can enable in the JSON to pre-enable extensions, that sounds reasonable too.

from vulkan-loader.

Comment by lenny-lunarg (MIGRATED)
Wednesday Sep 20, 2017 at 17:35 GMT

Sorry for the delay on this issue. I still haven't looked into exactly what this failure is, but I am working on a patch that will allow implicit layers to intercept functions like vkEnumerateInstanceExtensionProperties which are called before an instance is created. This is done to allow implicit layers to hide things that they won't support. This won't directly address your problem, but it is related. I'll look into this specific issue in more detail shortly.

So the main thing here is I'm not ignoring this issue, I just haven't had a chance to look into this, but I will shortly.

from vulkan-loader.

It is now possible to intercept these functions from implicit layers. As for the part about calling into the function, I think this is just a known limitation and we might address it as part of a broader layer interface rework, but I don't expect to do that.

from vulkan-loader.