What does messages "can't find IRQ for PCI INT A; probably buggy MP table" and "device [xxxx:yyyy] has invalid IRQ; check vendor BIOS" mean?

Issue

• Below messages are seen during every system boot:

Aug  3 14:06:01 hostname kernel: pci 0000:00:01.0: can't find IRQ for PCI INT A; probably buggy MP table
Aug  3 14:06:01 hostname kernel: pci 0000:00:01.1: can't find IRQ for PCI INT A; probably buggy MP table
Aug  3 14:06:01 hostname kernel: pci 0000:00:02.0: can't find IRQ for PCI INT A; probably buggy MP table
Aug  3 14:06:01 hostname kernel: pci 0000:00:02.1: can't find IRQ for PCI INT A; probably buggy MP table
Aug  3 14:06:01 hostname kernel: pci 0000:00:02.2: can't find IRQ for PCI INT A; probably buggy MP table
Aug  3 14:06:01 hostname kernel: pci 0000:00:02.3: can't find IRQ for PCI INT A; probably buggy MP table
Aug  3 14:06:01 hostname kernel: pci 0000:00:03.0: can't find IRQ for PCI INT A; probably buggy MP table
Aug  3 14:06:01 hostname kernel: pci 0000:00:03.1: can't find IRQ for PCI INT A; probably buggy MP table
Aug  3 14:06:01 hostname kernel: pci 0000:00:03.2: can't find IRQ for PCI INT A; probably buggy MP table
Aug  3 14:06:01 hostname kernel: pci 0000:00:03.3: can't find IRQ for PCI INT A; probably buggy MP table
Aug  3 14:06:01 hostname kernel: pci 0000:00:11.0: can't find IRQ for PCI INT A; probably buggy MP table
Aug  3 14:06:01 hostname kernel: pci 0000:00:1c.0: can't find IRQ for PCI INT A; probably buggy MP table
Aug  3 14:06:01 hostname kernel: pci 0000:00:1c.7: can't find IRQ for PCI INT D; probably buggy MP table
...
Aug  3 14:06:01 hostname kernel: pcieport 0000:00:01.0: device [8086:3c02] has invalid IRQ; check vendor BIOS
Aug  3 14:06:01 hostname kernel: pcieport 0000:00:01.1: device [8086:3c03] has invalid IRQ; check vendor BIOS
Aug  3 14:06:01 hostname kernel: pcieport 0000:00:02.0: device [8086:3c04] has invalid IRQ; check vendor BIOS
Aug  3 14:06:01 hostname kernel: pcieport 0000:00:02.1: device [8086:3c05] has invalid IRQ; check vendor BIOS
Aug  3 14:06:01 hostname kernel: pcieport 0000:00:02.2: device [8086:3c06] has invalid IRQ; check vendor BIOS
Aug  3 14:06:01 hostname kernel: pcieport 0000:00:02.3: device [8086:3c07] has invalid IRQ; check vendor BIOS
Aug  3 14:06:01 hostname kernel: pcieport 0000:00:03.0: device [8086:3c08] has invalid IRQ; check vendor BIOS
Aug  3 14:06:01 hostname kernel: pcieport 0000:00:03.1: device [8086:3c09] has invalid IRQ; check vendor BIOS
Aug  3 14:06:01 hostname kernel: pcieport 0000:00:03.2: device [8086:3c0a] has invalid IRQ; check vendor BIOS
Aug  3 14:06:01 hostname kernel: pcieport 0000:00:03.3: device [8086:3c0b] has invalid IRQ; check vendor BIOS
Aug  3 14:06:01 hostname kernel: pcieport 0000:00:11.0: device [8086:1d3e] has invalid IRQ; check vendor BIOS
Aug  3 14:06:01 hostname kernel: pcieport 0000:00:1c.0: device [8086:1d10] has invalid IRQ; check vendor BIOS
Aug  3 14:06:01 hostname kernel: pcieport 0000:00:1c.7: device [8086:1d1e] has invalid IRQ; check vendor BIOS