Altera PCI Express Development Kit: Linux DMA Driver

Yes, it looks like irq_line is assigned two different values, first from reading the appropriate configuration byte, then with the line above. Probably left over from testing the driver. I would say that "irq_line = dev->irq;" is the more important line in the driver, since the variable discards what it receives from the configuration byte and uses this value. So you could delete the pci_read_config_byte line and the printk statement that prints its value. But it provides a nice little bit of debugging info and it works just fine.