Re:It's never easy, is it?

[Adam <adam@xxxxxxxxxxxxxxxx>]

 From          : klug>klug-request
 To            : adam
 Subject       : Re:It's never easy, is it?
 Date          : 08/02/99 11:13


>>>My Current setup is cua4, IRQ4.  My modem only appears to allow IRQs 3 & 4
>>>on cua4.~
>>Don't you just love crappy PC hardware sometimes.~
>Yes, less and less.~

On days like these I mis my RS/6000 and IBM X-station.  Aren't PC's
supposed to be progress?

>>When you switched IRQ's~
>>did you move the modem or the mouse to a diffrent IRQ.  COM1=irq4 and~
>>COM2=irq3 in case you didn't know.
>I didn't know this.  I moved the modem.  The modem was on cua4, IRQ3.  I
>moved it to cua4, IRQ4.  (Note, I see a conflict here, considering your above
>statement.)~

IRQ 0 = System Clock
IRQ 1 = Keyboard~
IRQ 2 = See IRQ 9
IRQ 3 = COM2~
IRQ 4 = COM1~
IRQ 5 = Second printer port if you have one~
IRQ 6 = Floppy Drive Controller~
IRQ 7 = (lp0 in 2.2.x) or (lp1 in 2.0.x)~
IRQ 8 = CMOS Real Time Clock~
IRQ 9 = IRQ2 (the tie between the 8 & 16 bit bus)~
IRQ 10 =~
IRQ 11 =~
IRQ 12 = PS/2 mouse port,  if you have one.~
IRQ 13 = Floating Point Unit~
IRQ 14 = IDE0 (first ide channel)~
IRQ 15 = IDE1 (send ide channel, if you have one).~

>>When you boot what serial ports does  Linux find.  (dmesg | grep tty).
>Okay, I did this once and saw 3 tty statements using interrupts 2 and 3.  I
>didn't know what this meant.  I can do it again tonight and see what it says
>now that I've swapped the modem around.  I'll let you know.~

If at all possible I recommend moving the modem to irq 5.  This puts it
safely out of the way.  Also if you have an ATI video card (at least of the~
MACH series) you cannot use com4 (cua3) as that address is used by the video~
card.  It may SEEM to work,  but strange things will happen.  If you only~
have one serial port on your machine (say com1/cua0) then try to use the~
standard serial port you lack (com2/cua1) as it makes life a lot easier.~


>> You may have to use the~
>> setserial utility to slide the irq assignments
>>arround.~
>Will "man setserial" tell me much or should I look elsewhere?

Yes.  Basically if Linux detects a serial port at some address it will assign
it a tty number (you'll see that in dmesg), but it may not be able to detect
what IRQ line it is.  setserial lets you tell linux something like "the
third serial port should use irq 5" (setserial /dev/ttyS2 irq 5).  Trying
to auto-sense irq values for things like serial ports can be dangerous
(lead to lock ups) so Linux doesn't try very hard.~