Messages that complain about failures to allocate I/O resources might appear in POST, and in log files.
For example, you might see:
Sep 8 15:50:49 nsg14-28 kernel: PCI: Failed to allocate I/O resource #2:20@0 for 0000:8d:00.0 Sep 8 15:50:49 nsg14-28 kernel: PCI: Failed to allocate I/O resource #2:20@0 for 0000:8d:00.1
BIOS tries to allocate I/O resources. If it is unable to allocate I/O resources successfully, it displays error messages.
The OS might try as well. However if it tries, it fails and generates additional failure messages because it uses the same method as BIOS. However, most drivers can manage this condition.