Pro inspiraci: Dva COMy na jednom IRQ.

[Marek Kubita]

On Sat, 8 Feb 1997, Jan Kybic wrote:

> s malou  prestavkou jsem se opet vrhl
> na ukol  zprovoznit  pod Linuxem  sve  tri COMy:   COM1(IRQ4) je  mys,
> COM2(IRQ3) je  modem a COM3(IRQ4) je terminal. [...]

> Soudim, ze jelikoz oba porty funguji, hardwarovy problem to neni. Proc
> to tedy ten Linux neumi? Zatim mam dve prozatimni reseni:
> 1. Operativne startovat/ukoncovat gpm pri praci s terminalem :-(
> 2. Pomoci 'setserial /dev/cua? irq   2'  prepnout driver pro jeden   z
>    portu  z  interrupt do polling   rezimu.  To funguje,   ale neni to
>    nejrychlejsi (v zavislosti na velikosti bufferu v UART cipu), a 
>    zbytecne to zatezuje system. 

COMum je treba priradit ruzna IRQ - aspon tak se to vsude pise, vcetne
Serial-HOWTO: 

  9.  Can I use more than 2 serial devices?
  ...
  The number of serial ports you can use is limited by the number of
  interrupts (IRQ) and port I/O addresses we have to use.  This is not a
  Linux limitation, but a limitation of the PC bus.  Each serial devices
  must be assigned it's own interrupt and address.  A serial device can
  be a serial port, an internal modem, or a multiport serial board.

Nejde-li prestavit IRQ na seriove desce, mohlo by jit u modemu - u
internich modemu se vetsinou pocita s tim ze maji umet fungovat jako treti
seriovy port. Zkusil bych ho nakonfigurovat na COM3 a volne IRQ (5?). 
Je-li to switchuuprosty Plug&Play, doporucuji isapnptools (na
ftp.redhat.com, mirror SUNSITE). 

--- Marek Kubita                           home: kubitovi na mbox.lantanet.cz
                                           work: marek na corpus.cz