now modem only works on IRQ 0 (was: pci hardware modem not working)

[L W <ledawa@softhome.net>]

Thanks for the advice, it helped me figure out how to get the I/O from lspci 
-v.  I've got the modem *sort of* working now:  It seems to only work on IRQ 
0 (shared with the timer), and at speeds no higher than 9600 baud.  Examples:

# lspci -v
0000:02:0b.0 Serial controller: 5610 56K FaxModem 56K FaxModem Model 5610 (rev 
01) (prog-if 02 [16550])
        Subsystem: U.S. Robotics: Unknown device 0110
        Flags: medium devsel, IRQ 23
        I/O ports at 2400 [size=8]
        Capabilities: [dc] Power Management version 2

# setserial /dev/ttyS4 irq 23 port 0x2400 uart 16550A
# setserial /dev/ttyS4
/dev/ttyS4, UART: 16550A, Port: 0x2400, IRQ: 23, Flags: Fourport

# wvdialconf wvdial.conf
Scanning your serial ports for a modem.

Port Scan<*1>: Scanning ttyS4 first, /dev/modem is a link to it.
ttyS4<*1>: ATQ0 V1 E1 -- failed with 2400 baud, next try: 9600 baud
ttyS4<*1>: ATQ0 V1 E1 -- failed with 9600 baud, next try: 115200 baud
ttyS4<*1>: ATQ0 V1 E1 -- and failed too at 115200, giving up.
ttyS0<*1>: ATQ0 V1 E1 -- failed with 2400 baud, next try: 9600 baud

# setserial /dev/ttyS4 port 0x2400 uart 16550A autoconfig
# setserial /dev/ttyS4
/dev/ttyS4, UART: 16550A, Port: 0x2400, IRQ: 0, Flags: Fourport

# wvdialconf wvdial.conf
Scanning your serial ports for a modem.

Port Scan<*1>: Scanning ttyS4 first, /dev/modem is a link to it.
ttyS4<*1>: ATQ0 V1 E1 -- OK
ttyS4<*1>: ATQ0 V1 E1 Z -- OK
ttyS4<*1>: ATQ0 V1 E1 S0=0 -- OK
ttyS4<*1>: ATQ0 V1 E1 S0=0 &C1 -- OK
ttyS4<*1>: ATQ0 V1 E1 S0=0 &C1 &D2 -- OK
ttyS4<*1>: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 -- OK
ttyS4<*1>: Modem Identifier: ATI -- 5601
ttyS4<*1>: Speed 4800: AT -- OK
ttyS4<*1>: Speed 9600: AT -- OK
ttyS4<*1>: Speed 19200: AT -- O
ttyS4<*1>: Speed 19200: AT -- O
ttyS4<*1>: Speed 19200: AT -- O
ttyS4<*1>: Max speed is 9600; that should be safe.
ttyS4<*1>: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 -- OK

Same thing in kppp, it works as long as I set the speed to 9600.  With these 
settings I can dial, connect, and use the internet, just very slowly.

For good measure, here is the result of cat /proc/interrupts.  Perhaps there 
is a problem with IRQ 23 being used by something else but getting assigned to 
the modem PCI slot as well?  I don't know.

# cat /proc/interrupts
           CPU0
  0:    1948244    IO-APIC-edge  timer
  1:       6219    IO-APIC-edge  i8042
  7:          2    IO-APIC-edge  parport0
  8:          4    IO-APIC-edge  rtc
  9:          0   IO-APIC-level  acpi
 12:      68492    IO-APIC-edge  i8042
 14:      16385    IO-APIC-edge  ide0
 15:      20001    IO-APIC-edge  ide1
 16:          0   IO-APIC-level  uhci_hcd
 17:     244877   IO-APIC-level  Intel ICH4, eth0
 18:          0   IO-APIC-level  uhci_hcd
 19:          0   IO-APIC-level  uhci_hcd
 23:          0   IO-APIC-level  ehci_hcd
NMI:          0
LOC:    1948448
ERR:          0
MIS:          0