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Old 05-05-05, 06:52 PM   #107
nagual.hsu
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Join Date: Feb 2005
Posts: 19
Default Re: Trying to make headway into finding the Xid crashes source...

About IRQ sharing:

If I remember correctly, you can make an device to use a different
IRQ. However, when you do this, you will end up with changing an
IRQ of a group of devices(chips). That means, if they now share
the same IRQ, you can not isolate one of them and change the IRQ
of it 'cause they share the same IRQ line, an hardwire line. But why bios
offers such a function? I guess there's a reason about it. And that's the
different priorities of different IRQs. Some IRQ is the highest priority(ie.
IRQ 0).....

I don't know how APIC works in concepts. But it seems there's nothing
software/kernel/drivers can do about it. I've tried changing IRQs couple
of month ago but in vain.(not exactly what I wanted.) Then I did googling,
and found what I said in the beginning of this post. However, we do ask
an mainboard vendor to isolate 4 IRQs each for 4 devices and it works.
I don't know how they make it. But they say about changing the firmware
of the bios.(This somehow contradicts what I found in googles.). Yes,
I guess there's some switch array (hardware) that does this job routing
some lines together so that some devices can share the same IRQ. And
this switch array is controlable by the firmware of the bios.

nagual

Last edited by nagual.hsu; 05-05-05 at 07:04 PM.
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