1) When you say "One of our Dell R630 machines in our CI environment won't boot with the 4.4.0-168.197 kernel in xenial." , does this mean that you have other Dell R360 machines that *do* boot with the new xenial kernels?
2) Can you clarify what you mean by "I also tried installing xenial on the machine, and the same happens with grub. No output in the console after selecting the kernel in the grub menu, it just reboots." ? How is "installing xenial" different from what you were doing prior to that? Is it a matter of booting from a live-usb vs booting from PXE ? If that's the case, do you know what kernel this xenial image was using? Did the live instance come up at all?
I think the easiest thing would be to try to bisect to find the offending commit. Attempting to boot the 4.4.0-167.196 kernel is a good idea, to help us know where to start bisection.
Thanks for the info @Björn
I have a couple of initial questions
1) When you say "One of our Dell R630 machines in our CI environment won't boot with the 4.4.0-168.197 kernel in xenial." , does this mean that you have other Dell R360 machines that *do* boot with the new xenial kernels?
2) Can you clarify what you mean by "I also tried installing xenial on the machine, and the same happens with grub. No output in the console after selecting the kernel in the grub menu, it just reboots." ? How is "installing xenial" different from what you were doing prior to that? Is it a matter of booting from a live-usb vs booting from PXE ? If that's the case, do you know what kernel this xenial image was using? Did the live instance come up at all?
I think the easiest thing would be to try to bisect to find the offending commit. Attempting to boot the 4.4.0-167.196 kernel is a good idea, to help us know where to start bisection.
Thanks