Resolving IRQ Conflicts

[Mark Henri]

I've got a few conflicts (actually, too many devices I'm trying to run) on
my XP machine. Here's the map--

IRQ 00 System timer OK
IRQ 01 Standard 101/102-Key or Microsoft Natural PS/2 Keyboard OK
IRQ 03 Communications Port (COM2) OK
IRQ 04 Communications Port (COM1) OK

IRQ 05 ATI Technologies, Inc. 3D RAGE PRO PCI OK
IRQ 05 Adaptec AHA-2940AU PCI SCSI Controller OK
IRQ 05 M-Audio Delta 1010 OK

IRQ 06 Standard floppy disk controller OK
IRQ 08 System CMOS/real time clock OK
IRQ 09 Microsoft ACPI-Compliant System OK

IRQ 11 SiS 7001 PCI to USB Open Host Controller OK
IRQ 11 SiS 7012 Audio Driver OK
IRQ 11 SiS 900 PCI Fast Ethernet Adapter OK

IRQ 12 Microsoft PS/2 Mouse OK
IRQ 13 Numeric data processor OK
IRQ 14 Primary IDE Channel OK
IRQ 15 Secondary IDE Channel OK

Can I eliminate some things like--
- 15 Secondary IDE Channel
- 09 Microsoft ACPI-Compliant System?

Also, is it possible to use IRQ 2 and 7?

Thanks,

Mark

 

[Eric Warnke]

I've got a few conflicts (actually, too many devices I'm trying to run) on
my XP machine. Here's the map-- ....
IRQ 09 Microsoft ACPI-Compliant System OK

....

ACPI should make IRQ conflicts moot. It basicly allows the CPU
to manage IRQ's on a per card basis, not a system wide basis. If
you are experienceing a specific problem then please tell us
otherwise I would leave it alone.

Cheers,

 

[R. McCarty]

Newer systems have a system level component called an IRQ
Routing Hub. This extends the normal 15 IRQ range up into the
20's. IRQ Sharing would only have a negative impact on older
PCI cards that don't support sharing properly.

 

[GSV Three Minds in a Can]

Newer systems have a system level component called an IRQ
Routing Hub. This extends the normal 15 IRQ range up into the
20's. IRQ Sharing would only have a negative impact on older
PCI cards that don't support sharing properly.

Actually it can have a minor, going on medium, =performance= impact, if
something that generates a ton of interrupts get shared with a bunch of
things which have complex IRQ handling, and the 'right' one winds up at
the wrong end of the stack (when IRQ 'N' shows up, the XP kernel calls
each of the 'possible' handlers for that IRQ one after the other, until
someone finally admits it is 'their' card, and they turned the interrupt
off now. Afaik there is no easy way to determine the order of handlers
in the stack, and no heuristic re-ordering based on which driver turns
out to be handling the majority of the interrupts).

Not a problem with most modern devices which tend to interrupt once per
buffer-full (using =big= buffers and DMA), but some old devices can
generate a fair old flood (start, run, perfmon, and you can actually
graph the time spent in interrupt handling, if you really care).

 

[Malke]

The actual issue that I'm having is a problem with sound quality with
the
Delta 1010 card. I'm getting skips and pops and their documentation
said
to check for IRQ conflicts. Since their appears to be three devices
sharing the same IRQ, I thought they might be right? I've also had
problems when playing CD's also since I received the computer.

Although I'm not familiar with your particular card, skips and pops are
usually cured by updated the soundcard drivers. Try that first.

Malke

 

[Mark Henri]

Although I'm not familiar with your particular card, skips and pops are

usually cured by updated the soundcard drivers. Try that first.

Yeah, I tried that but it didn't seem to help. I'll probably contact the
manufacturer next. I liked that last discussion of IRQ allocation, good
insights.

Thanks,

Mark

 

[R. McCarty]

About IRQ's. Most motherboards have at least 2 PCI slots
that do not share an IRQ. Reference your motherboard manual,
but as a guide, Slots #2 & #5 are normally independent IRQ's.