Re: Drifting /dev/ttyS3 IRQ
*- On 26 Sep, Jonathan D. Proulx wrote about "Drifting /dev/ttyS3 IRQ"
> Hi,
>
> /dev/ttyS3 is my modem. The hardware is jumpered for IRQ 5.
> I added the following line to /etc/rc.boot/0setserial:
>
> ${SETSERIAL} -b /dev/ttyS3 irq 5 port 0x2E8 skip_test autoconfig ${STD_FLAGS}
>
> The problem is the irq frequently reverts to 3. This happens after
> closing my dial up connection (although not always). Also, starting X
> almost always closes my dialup connection (I don't know if this is
> related)
>
> Any thoughts???
>
Usually when X trips your modem it indicates an IRQ conflict with your
graphics card and modem. If I remember correctly IRQ's are not used in
console mode but are in graphics mode. Most graphics cards that I have
seen tend to use IRQ9(shared with IRQ2). Can you change the IRQ of the
modem to another unused IRQ? What are the results of 'setserial -bg
/dev/ttyS?' and 'cat /proc/interrupts'? Mine are not very consistent:
What is on each port
# setserial -bg /dev/ttyS?
/dev/ttyS0 at 0x03f8 (irq = 4) is a 16550A # ups signal cable
/dev/ttyS1 at 0x02f8 (irq = 3) is a 16550A # palm pilot & x10 module
/dev/ttyS2 at 0x6c00 (irq = 2) is a 16650 # mouse on pci serial card
/dev/ttyS3 at 0x02e8 (irq = 5) is a 16550A (spd_vhi) # internal modem
# cat /proc/interrupts
CPU0
0: 22708326 XT-PIC timer
1: 94804 XT-PIC keyboard
2: 0 XT-PIC cascade
3: 150829 XT-PIC serial
5: 6466259 XT-PIC serial
7: 12633 XT-PIC soundblaster
8: 89369 XT-PIC rtc
9: 12 XT-PIC serial
10: 2821283 XT-PIC NE2000
11: 1695958 XT-PIC tmscsim
12: 1232088 XT-PIC PS/2 Mouse
13: 1 XT-PIC fpu
14: 1321752 XT-PIC ide0
15: 1110224 XT-PIC ide1
NMI: 0
I have an AGP TNT card which doesn't seem to use an IRQ here. Maybe
other cards are different.
Don't know if I helped here or made things worse.
--
Brian
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