IRQ Questions

I just reinstalled Windows and things seem to be working okay. Except that it crashed once... I think that might have been TweakUI's fault. Anyway, I'm trying to figure out if there's a problem with my IRQ settings. Things didn't really start to screw up until I installed my new GeForce4 Ti4200. So I went to the mfg's website and read the FAQ. Seems there's a lot of IRQ issues. Looking in device manager I don't see any problems, but I'm still a little confused.

From the FAQ at

"I can't get AGP working, Direct-X Diagnostics fail, or I get lockups in games. How can I fix it?"

I don't have any of these problems specifically, but it made me look closer at my IRQ settings. Here's what they are:

00 - System timer

01 - Standard 101/102-Key or Microsoft Natural Keyboard

02 - Programmable interrupt controller

03 - ACPI IRQ Holder for PCI IRQ Steering

03 - 3Com EtherLink XL TPO 10Mb Ethernet Adapter

04 - Communications Port (COM1)

05 - ACPI IRQ Holder for PCI IRQ Steering

05 - VIA VT83C572/VT82C586 PCI to USB Universal Host Controller

05 - VIA VT83C572/VT82C586 PCI to USB Universal Host Controller

05 - NVIDIA GeForce4 Ti 4200

06 - Standard Floppy Disk Controller

07 - ECP Printer Port (LPT1)

08 - System CMOS/real time clock

09 - SCI IRQ used by ACPI bus

10 - Creative SB16 Emulation

11 - ACPI IRQ Holder for PCI IRQ Steering

11 - Creative SB Live!

13 - Numeric data processor

14 - VIA Bus Master PCI IDE Controller

14 - Primary IDE controller (dual fifo)

15 - VIA Bus Master PCI IDE Controller

15 - Secondary IDE controller (dual fifo)

According to the FAQ's answer, first, my card should be at IRQ11. This is clearly not the case. Does that really matter? If so, what can I do to fix that? My soundcard is already at 11.

Second, what the hell are those USB Universal Host Controllers? This site I found ( ) says the only thing that can share the same IRQ number is the IRQ Holder for PCI IRQ Steering. I'm thinking maybe those are my extra USB slots? My mobo came with a D-Bracket (diagnostic lights with two USB ports on them) and that's the only thing I can think of that would be, but I could be way wrong. My printer is the only thing plugged into either of those ports. Which, if I'm right in my assumption, would explain why before I reinstalled Windows turning on my printer caused my computer to reset spontaineously. I haven't used it as much on this install so I haven't seen that problem yet.

Blargh. I'm sorry it's such a long post, I really don't know what I'm up against here. I've tried looking around for answers but it's just so damn hard to pinpoint issues and get answers to specific questions. If anyone can help me out here I would greatly appreciate it. Should I be moving cards around, changing settings in Windows, BIOS...? Thanks much for any help.

edit: just thought I should add that I don't NEED those two USB ports on the D-Bracket. If this is indeed the problem I can always remove it if that's what's needed. I have other USB ports I can plug my printer to (or I could even use the old printer cable...)
Looking at your settings, I'd wonder if you've got the BIOS set to some strange settings for plug and play, since you should have COM2 on IRQ3, which isn't showing up anywhere (unless you've disabled it of course).

You might want to try resetting it to the defaults or at least checking the PnP settings are set to automatic. What Windows version are you using?
I'm using Win98 (not SE). I haven't done anything to the BIOS settings as far as PnP is concerned. I didn't disable COM2 either. Is this a BIOS related issue or a Windows related issue? It seems to me it could be either.

My plan was to boot into safe mode, disable the SB16 Emulation (I don't think I need that. IIRC that's for old DOS games and such, which I don't use), change the soundcard in Windows to IRQ10, change the video card to IRQ11, and reboot to normal. Is that a good idea? Would it be that easy to do?

Someone in a newsgroup suggested removing all cards but my video card, restarting to let the computer auto assign the IRQ. Then I would shut down, plug in another card, and repeat the process one card at a time until everything has it's own IRQ. My concern is that that won't really help the problem. It was autodetection that got me into this mess in the first place.

I guess my questions are 1) is how it's currently setup a problem? and 2) if it is, what's the best way to make sure everything has it's own IRQ?

I suppose I could start pulling cards and seeing what happens, but since my problem is not as simple as an error box on load I wouldn't really know if the problem is fixed right away. Right now it seems to work, but it gets flakey at times. I'm trying to narrow the scope as to what the problem might be. Maybe my motherboard just doesn't like my new card.

I really do appreciate the help you guys give. If there's any more info I can provide just ask!
try resetting the bios to the factory defaults first, if it still doesnt work then id suggest you pull out all the cards, as the person on the newsgroups suggested, then add them back in one by one

the best way to assign the irqs is using pnp anyway, but what you have there definitely doesnt look right (nic on irq 3 for example)

what cards do you still have of the isa variety?

do you have a ps/2 mouse port?

do you actually have a physical com2 port on the pc, and if so is it enabled in the bios?
it's perfectly normal for a semi-new ACPI capable PC to throw all kinds of cards onto the same irq (which can be nearly any).

there won't be probs, and if your system is running fine, why fuck with it till it stops working?
Originally posted by Arakon@Dec. 22 2002, 2:16 pm

it's perfectly normal for a semi-new ACPI capable PC to throw all kinds of cards onto the same irq (which can be nearly any).

there won't be probs, and if your system is running fine, why fuck with it till it stops working?

No, you're right (as usual). But it's not working perfectly. I've had a few glitches here and there that I'm trying to track the source of. I'm trying to narrow it down. It could easily be software issues. But when you turn on your USB printer only to have the screen go black and the computer reboot, something's up. Thing is, it doesn't do that every time. So I can't really figure out what the hell is going on. If you're saying that my setup is perfectly normal, then it must be something else. But I didn't have these issues until I installed my video card. So I thought maybe the two were related, especially since there's something with "USB" in with my videocard. I guess I'm more confused than anything else at this stage.

And to answer your questions megametal, yes, I do have two COM ports, and I don't have any ISA slots. I have a PS/2 mouse port, but I don't use it. I have a USB mouse that's plugged into the on-board USB port.
Check if you have the agp irq enabled in your bios, and the acpi functions, and the pnp os. Don't change the irq's with windows, that usually does more "damage".

Upgrade your windows, at least to win98se. You know, some compatibility issues exist because of that (new hardware with old buggy os is not a good combination). Check your drivers to be win certified ones, not betas (specially sblive, nvidia & via 4in1 ones).

You can always deactivate any device you don't need through your BIOS, not the win device manager.

Ah, and try to change slots for the pci devices.

Anyways, I can get rid of that buggy videocard of yours