On another mailing list I inhabit, someone is trying to set up a new
motherboard. It has facilities for 14 peripheral interrupts beside the
usual ones.
The interrupt table (from a ix86 pc) is _weird_!
(from the Bios)
IRQ Assignments for this motherboard
(S=shared U=used) [not present components]
===================================================
A B C D E F G H
--------------------------- -- -- -- -- -- -- -- --
pci slot 1 - - - - - S - -
pci slot 2 - - - - - - S -
pci slot 3 - - - - - - - S
pci slot 4 - - - - S - - -
pci slot 5 - - - - - S - -
pci slot 6 - - S - - - - -
AGP slot S - - - - - - -
onboard USB controller HC0 S - - - - - - -
onboard USB controller HC1 - - - U - - - -
onboard USB controller HC2 - - S - - - - -
onboard USB 2.0 controller - - - - - - - S
onboard LAN - - - - S - - -
[onboard RAID - - - - - - - S]
[onboard 1394 - - - - - - S -]
----------------------------------------------------
Now whan you include rtc, serial & parallel, etc they come up to way
over 16 irqs. There's an onboard soundcard in there onboard as well.
What's the story?
Anyone got a good explanation or url for this technology? Conventional
wisdom would be that irq sharing is the surest way to a crash in a pc.
The owner is a software expert setting up linux on the thing, and with a very
recent (alpha or beta) kernel, (to handle the chipset)and the problems are:
1. Conventional devices keep SHARING and being assigned half-assed or
weird irq numbers by the bios.Is there any utility for farting around with
these irq assignmentsarting around with these irq assignments?
2. She can't get the concert playing in tune. I have a detailed
e-mail (down to the nitty-gritty of C code) which is long, but I'll gladly
post it if people want to see it, or send it to those who know the area
off list. She is trying to figure the hardware from kernel code, surely
the most painful way to do it!! She has built a 'distro' type kernel,
with all the modules, so she can fool around with it more once it's
running
3. It's assigned the hd to irq 4, then (different kernel) to irq 9.
Can 9 be safely used? I've got away with it, but Somebody thinks 9
should not be used, as 2 is/was masked over to it to give 16 interrupts.
He's muttering about the PC/XT 8259A Apic - a little before my time with
pcs. Is that still an issue?
It is probable she would install windows temporarily if that was the
only fix and she could wipe it again straight away.
--
With best Regards,
Declan Moriarty.
--
Author: Declan. Moriarty
INET: [EMAIL PROTECTED]
Fat City Network Services -- 858-538-5051 http://www.fatcity.com
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