[Resend, originally sent to the lkml] The serial_pci driver tries to guess serial ports on unknown devices based on the PCI class (modem or serial). On certain softmodems (AC'97 modems) this can lead to the recognition of non-existing serial ports like this: 0000:00:08.0: ttyS1 at I/O 0x8828 (irq = 3) is a 8250 0000:00:08.0: ttyS2 at I/O 0x8840 (irq = 3) is a 8250 0000:00:08.0: ttyS3 at I/O 0x8850 (irq = 3) is a 8250 0000:00:08.0: ttyS4 at I/O 0x8860 (irq = 3) is a 8250 0000:00:08.0: ttyS5 at I/O 0x8870 (irq = 3) is a 8250 This actually disables the use of the hsfmodem 3rd party driver if 8250 is compiled into the kernel e.g. to provide a boot-time serial console. This patch adds a blacklist of PCI IDs that are to be ignored by the driver. The patch applies against both 2.6.21.5 and 2.6.22-rc7. Signed-off-by: Christian Schmidt