[Linux-parport] IRQ 7
mduncan at mail.psislidell.com
Mon Nov 1 09:37:46 EST 2004
I have a question about irq 7. I have a special DAQ device attached to
the parallel port. At given times this device raises the voltage on pin
10 (I think) causing an interrupt on IRQ 7. I have a simple device
driver that handles this interrupt and services a special device read.
On one box this all works fine, on other boxes it doesn't seen to work
at all. The only difference I can see is that on the working machine I
can grep /var/log/messages and get a line that reads:
Oct 29 13:39:15 fldas kernel: parport0: irq 7 detected
But on the non-working machine I do not get this message. Both machines
say the parport is detected at 0x378. I also have trouble when
installing an adapter card. The additional parports (parport1 parport2)
are detected but only one "irq 7 detected" message for parport0.
What does the "irq7 detected" mean, and what do I need to do to "detect"
IRQ 7 when it isn't at boot? Also, how do I get the adapter card to
generate interrupts on IRQ7? Any help is GREATLY appreciated.
Planning Systems Inc.
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