Rtai and Serial ports above ttyS1

Paolo Mantegazza mantegazza at aero.polimi.it
Fri Jun 23 14:57:02 CEST 2006


Godzil wrote:
> 
> Le 23 juin 06 à 11:33, Laurent.Kersten at alcatelaleniaspace.com 
> <mailto:Laurent.Kersten at alcatelaleniaspace.com> a écrit :
> 
>>
>> Hello Manoel,
>>
>> No, according to me 4 ports are set
>>
> 
> Yes, that right, /proc/tty/driver/serial report 4 ports :
> 
> taipan ~ # cat /proc/tty/driver/serial
> serinfo:1.0 driver revision:
> 0: uart:16550A port:000003F8 irq:4 tx:771 rx:0 RTS|DTR
> 1: uart:16550A port:000002F8 irq:3 tx:266 rx:0 RTS|DTR
> 2: uart:16550A port:000003E8 irq:10 tx:0 rx:0
> 3: uart:16550A port:000002E8 irq:11 tx:0 rx:0
> 
> and ioports are reserved:
> 
> taipan ~ # cat /proc/ioports
> [...]
> 02e8-02ef : serial
> 02f8-02ff : serial
> [...]
> 03e8-03ef : serial
> [...]
> 03f8-03ff : serial
> [...]
> 
> 
>> ttyS2 and ttyS0 share the same line as well as ttyS3 and ttyS1.
>> This is the way it works for legacy ISA serial.
>>
> 
> yes, but even selecting different IRQ, linux always try to set IRQ to 4 
> or 3, I known that ISA don't have PnP facility like PCI (or only on 
> really recent ISA card, but this one don't have things like that and IRQ 
> are selectable only via jumpers)
> 
> and I can set IRQ to 3, 4, 9 10 or 11, but on none the card work..
> 
>> Read carefuly the I/O Address they are all different (2*e*8, 
>> 2*f*8,3*e*8,3*f*8) each of the ports uses 8 bytes.
>>
> 
> Yes and correspond to the first 2 ports of the card :
> 
> COM-A  =  3E8  =  COM3 
> COM-B  =  2E8  =  COM4 
> COM-C  =  338  =  COM5 
> COM-D  =  238  =  COM6
> 
> But even playing with setserial trying to change IRQs nothing seems to 
> work.. maybe my cable from card to DB9 is incorrect (my null modem cord 
> work correctly with mainboard onboard serials, so it's working)
> 
> ---
> 
> By the way, (and it's more directly RTAI related) is there is a way to 
> say to rtai_serial to not use a specific serial port ? I need to have a 
> serial console on /dev/ttyS0 but when rtai_serial is inserted, no more 
> linux serial is working (and using them tends oftenly to crash the system..)
> 

I think the port selection is controlled by on board logic hw. Usually 
there are jumpers or dip switches to choose it.

Paolo.





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