I’m running 3.10.0 (CentOS 7.3) on a Supermicro X10SDV-8C-TLN4F motherboard, which has a 16550A on it. What’s odd is that when I look in /dev/ I see ttyS0…S3, even though there are only 2 hardware ports (a single DUART). [root@kvm2 logwatch]# setserial -G /dev/ttyS0 /dev/ttyS0 uart 16550A port 0x03f8 irq 4 baud_base 115200 spd_normal skip_test [root@kvm2 logwatch]# setserial -G /dev/ttyS1 /dev/ttyS1 uart 16550A port 0x02f8 irq 3 baud_base 115200 spd_normal skip_test [root@kvm2 logwatch]# setserial -G /dev/ttyS2 /dev/ttyS2 uart unknown port 0x03e8 irq 4 baud_base 115200 spd_normal skip_test [root@kvm2 logwatch]# setserial -G /dev/ttyS3 /dev/ttyS3 uart unknown port 0x02e8 irq 3 baud_base 115200 spd_normal and dmesg says: [ 3.173481] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled [ 3.194077] 00:03: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A [ 3.214710] 00:04: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A I was trying to figure out where this happens, and why, so maybe I could submit a patch to allow one to suppress this behavior (say with “8250.only_real_hw=1” or some other module parameter). Not sure where this is happening. Thought it might be in drivers/tty/serial/8250/8250_pnp.c but nothing stands out. Anyone know the backstory on why this happens, and how to (conditionally) change this behavior? Thanks, -Philip -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
