Tips for running starfield via Steam and Proton

If it is helpful to others, I was able to get Starfield to work with Steam with my AMD system.

I understand that folks using AMD cards have generally had a lot more success; this probably won't help nvidia users.

I'm using Kubuntu 22.04.3 LTS, an AMD Ryzen 9 5900X CPU, and AMD RX 6800 XT video card. I'm not a big fan of using PPA repos, but I am using the Mesa 23.1.8 libraries from kisak-mesa PPA. I am using experimental proton in Steam.

My symptom was that Starfield would install and load, but crash trying to start a new game. /var/log/kern.log had errors similar to 'Waiting for fences timed out' and 'ERROR failed to halt cp gfx'.

The latest kernel from Canonical available via apt is 5.15.0.84. What solved the problem for me was a newer kernel. I did this today, so I was successful by building 6.5.4.

Be careful: your mileage may vary here and installing a new kernel comes with risks. Backing up your system is always a good idea.
I've found that as long as I leave known stable kernels available in my grub boot-loader, this isn't scary - I can reboot and select the safe kernel. However, if you're uncomfortable troubleshooting and don't have a second system to search for help and answers, give your recovery strategy some thought before proceeding.

I've found that this guide is a nice straightforward one for building and installing a new kernel:
https://phoenixnap.com/kb/build-linux-kernel

I deviate from this guide in two ways (I'm not being super verbose here - you may have to figure some of this out or search for more info, but I hope it will get you going in a direction):

1. make will almost certainly fail due to not being able to sign the new kernel. Side note: make is verbose. If it fails, it may not be clear why. Try running it a second time to get a more succinct message of what is failing.
   The linked guide suggests working around the cert errors by disabling secure booting in the kernel. Instead, I installed the source for my current kernel (e.g. apt-get install linux-source-5.15.0) and copied over the certificates I needed. For example:
   cp -v /usr/src/linux-source-5.15.0/debian/canonical*.pem ~/newkernelsource/debian/
cp -v /usr/src/linux-source-5.15.0/debian/certs/* ~/newkernelsource/debian/certs/

2. You can allow make to run multiple jobs concurrently, which can reduce the build time. Just ensure it is fewer jobs than you have cores. I have 24 cores, so I use something like:
   make -j 20

After rebooting with the new kernel, the game fired right up.

Hope this helps someone.