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Date:      Wed, 24 Jun 1998 19:44:34 +0000
From:      labrinop@pop.vaniercollege.qc.ca
To:        tijmen@dse.nl
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   re: kernel stray irq 7
Message-ID:  <199806242346.TAA22176@pteradactyl>

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On Wed, 24 Jun 1998 Tijmen Ramakers wrote:

> I frequently get a message '/kernel: stray irq 7', at seemingly 
> random moments. Can anyone tell me what it means?

This may be due to two things AFAIK:

1)  IRQ 7 is used by the parallel port, which you say is broken.
Since the interrupt must be enabled by a bit in the port register i 
don't thing this is the cause of the 'stray irq 7'. (IMO)

2)  IRQ 7 can also be generated by the 8259 Programmable Interrupt 
Controller (PIC) when the Interrupt Reuest (IR) line does not remain 
high until the falling edge of the Interrupt Acknowledge (INTA) line.
This is called a spurious interrupt and generates what Intel calls a 
DEFAULT IRQ  7, which shows up as an unmaskable irq 7 without an 
interrupting device (determined by PIC status bits), this is most 
likely the  cause of the 'stray irq 7'. (again IMO)

  It is possible that you have a card that does not generate proper 
interrupt signals, i once had a 486 mother-board where the hd 
controller card generated a DEFAULT IRQ 7 for every controller 
interrupt (irq 14). In DOS , irq 7 is simply ignored (handler does an 
interrupt return), but FreeBSD must capture it.

  Run 'vmstat -i' to show what the interrupt is doing.

Sincerely, PeterL

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