when I try to connect a serial line to /dev/ttyS*
I get an error

cat: /dev/ttyS3: Input/output error

I read on another forum that the GPIO pins can be wrong for my specific hardware, Intel Duo Processor T7200 on Toshiba and this could be causing the input/output errror. How can I find this out?

Here's the setserial output:

# setserial -ag /dev/ttyS*
/dev/ttyS0, Line 0, UART: unknown, Port: 0x03f8, IRQ: 4
Baud_base: 115200, close_delay: 50, divisor: 0
closing_wait: 3000
Flags: spd_normal skip_test

/dev/ttyS1, Line 1, UART: unknown, Port: 0x02f8, IRQ: 3
Baud_base: 115200, close_delay: 50, divisor: 0
closing_wait: 3000
Flags: spd_normal skip_test

/dev/ttyS2, Line 2, UART: unknown, Port: 0x03e8, IRQ: 4
Baud_base: 115200, close_delay: 50, divisor: 0
closing_wait: 3000
Flags: spd_normal skip_test

/dev/ttyS3, Line 3, UART: unknown, Port: 0x02e8, IRQ: 3
Baud_base: 9600, close_delay: 50, divisor: 0
closing_wait:

help very much appreciated