How to update packages to intermediate or most recent possible version with pacman?

Question

I think a case study is better to understand what I mean. I have cuda 9.0.176 and cuddn 7.1.4 installed. The most recent version of cudnn is 7.3.0, but it depends on cuda >= 10 and for unrelated reasons, I can't upgrade cuda. I can, however, upgrade cudnn to version 7.2.1, which is available in the archives and whose dependencies I already have installed. However, pacman -S does not upgrade my packages to these intermediate versions, so my cudnn package stays even more outdated than necessary. Is there a way to upgrade packages in this a situation without having to manually download and install them with pacman -U?

Answer 1

You can use the Arch Linux Archive to sync your entire system to a unified date somewhere in the past that has the desired version of cuda.

It's also possible to hold back the cuda version, rebuilding it if/when needed for changing soname dependencies, and building custom cudnn/other packages which specifically depend on your older cuda package. This requires work to maintain yourself, but allows you to safely update your system.

I'm not personally familiar with cuda, but you should be able to use any of various AUR packages for cuda-7.0, cuda-7.5, cuda-8.0 cuda-9.1, cuda-9.2 etc. to partially automate this for you. There is also a cudnn6 package.