Hi,
I am trying to upgrade the linux kernel on my PC from version 5.3.4 to 5.5.8 on an old Pentium-D desktop. Unfortunately, the system hangs during the startup of the kernel. I have tried, a few things, but I do not manage to troubleshoot this effectively.

The following happens:
[ 0.477237 ] pci 0000:00:01.0: ASPM: current common clock configuration is broken, reconfiguring.
[ 0.477441 ] pci 0000:00:01.0: PCI bridge to [bus 01]
[ 0.477553 ] pci 0000:00:01.0: bridge window [io 0xc000-0xcfff]
[ 0.477664 ] pci 0000:00:01.0: bridge window [mem 0xfdd00000-0xfddfffff]
[ 0.477775 ] pci 0000:00:01.0: bridge window [mem 0xd0000000-0xdfffffff 64bit pref]
[ 0.478082 ] pci 0000:00:1c.0: PCI bridge to [bus 02]

then the system hangs.

Any idea, how I should proceed troubleshooting?

Luc

Try booting with "acpi=off" on the kernel command line. If that boots, try "pci=noacpi". There are other options for partly disabling pci. See the command line page at kernel.org for a full list.

You can try any of these out without it doing your system any harm. If you can find some command line options that work while others don't, that will allow someone here to zero in on the problem.

Looks like the pci bridge might be an issue as a wild guess.

Boot to prior kernel and see if the you log this information and see what the next line is maybe.

Do you have access to a device that can be used to try to login remotely after reaching the apparent hang? Sometimes a "hang" isn't total, and dmesg and journal info can be retrieved via remote to identify the problem.

Since you have very old hardware it would be best if you use an LTS kernel such as 4.19 LTS instead of trying to use the 'latest' kernel as you don't need the latest hardware support. You may avoid all of these problems.

You never mentioned what distro you are using. Some support a choice of kernel branches such as current or LTS.

I have a 2011 era 2nd generation i7-2600K which is much newer than your Pentium-D and it runs fine with 4.19 on Manjaro. The Manjaro installer auto-selected the LTS kernel for my older hardware.