"serial" does not show up in /proc/interrupts

"serial" does not show up in /proc/interrupts

[Thomas Hood]

I am looking for the cause of an oops (more info
to come in another message) and I noticed the following
anomaly.  I am using a modular serial driver on /dev/ttyS0
and /dev/ttyS1 (actually /dev/tts/0 and /dev/tts/1 under
devfs).  See the listing of my /proc/interrupts below.
I am not using /dev/ttyS0 at the moment, so IRQ4 isn't listed
as used.  I assume that's normal.  But I do have /dev/ttyS1
open; it uses IRQ3.  But note that the name of the serial
driver is not printed in the list.  Why not?

root@thanatos:~# cat /proc/interrupts
           CPU0       
  0:      65078          XT-PIC  timer
  1:       1546          XT-PIC  keyboard
  2:          0          XT-PIC  cascade
  3:       1979          XT-PIC  
  5:       3324          XT-PIC  CS4231
  7:          4          XT-PIC  parport0
  8:          1          XT-PIC  rtc
 10:         27          XT-PIC  mwave_3780i
 11:       5021          XT-PIC  usb-uhci, Texas Instruments PCI1250, Texas Instruments PCI1250 (#2)
 12:       3268          XT-PIC  PS/2 Mouse
 14:       8807          XT-PIC  ide0
 15:          4          XT-PIC  ide1
NMI:          0 
ERR:          0

Fishy!

--
Thomas Hood
jdthood_AT_yahoo.co.uk

Re: "serial" does not show up in /proc/interrupts

[Stuart MacDonald]

From: "Thomas Hood" <jdthoodREMOVETHIS@yahoo.co.uk>
> I am not using /dev/ttyS0 at the moment, so IRQ4 isn't listed
> as used.  I assume that's normal.  But I do have /dev/ttyS1

That is normal. serial.c unregisters the irq if it's no longer
needed.

> open; it uses IRQ3.  But note that the name of the serial
> driver is not printed in the list.  Why not?
>
>   3:       1979          XT-PIC

If you have it open, it should appear.

> Fishy!

Indeed.

..Stu