i was able to solve this issue,i tried to install detectron2 version 0.4 after updating pytorch,cuda,cudnn etc,i had version missmatch,i had pytorch latest version installed but cuda 10.2 installed,so because of that detectron2 was not running in my pc and showed me error like you are getting,you need to install latest pytorch,cuda,cudnn,nvcc etc and after that you need to check if all package version is similar or there is no version missmatch among those and then you will be able to run detectron2 on rtx3090,i carefully set up my environment by following this beautiful tutorial : https://medium.com/analytics-vidhya/install-cuda-11-2-cudnn-8-1-0-and-python-3-9-on-rtx3090-for-deep-learning-fcf96c95f7a1 33
follow step by step procedure and make sure you are not making any mistakes,once done,you will be able to run detectron2 on rtx3090 like i did,if you still can’t then surely you missed something from here : https://medium.com/analytics-vidhya/install-cuda-11-2-cudnn-8-1-0-and-python-3-9-on-rtx3090-for-deep-learning-fcf96c95f7a1 33
so carefully follow the tutorial and best of luck