IRQ's in WinXP

Mike_W · Post by **Mike_W** » Fri Apr 26, 2002 12:06 am

Microsoft Information

In Windows, peripheral component interconnect (PCI) devices can share IRQs. In accord with the Plug and Play capability that is defined by the PCI specification, adapters are configured by the computer BIOS and are then examined by the operating system and changed if necessary. It is normal behavior for PCI devices to have IRQs shared among them, especially on Advanced Configuration and Power Interface (ACPI) computers that have Windows ACPI support enabled.

In Windows XP, Device Manager may list some or all of the devices on your ACPI motherboard as using the same IRQ (IRQ 9). (To view the list of resources, click either Resources by type or Resources by connection on the View menu). No option is available to change the IRQ setting. Windows takes advantage of the ACPI features of the motherboard, including advanced PCI sharing. The PCI bus uses IRQ 9 for IRQ steering. This feature lets you add more devices without generating IRQ conflicts.

Note that Windows XP cannot rebalance resources in the same way that Microsoft Windows 98 does. After PCI resources are set, they generally cannot be changed. If you change to an invalid IRQ setting or I/O range for the bus that a device is on, Windows XP cannot compensate by rebalancing the resource that was assigned to that bus.

Windows XP does not have this ability because of the more complex hardware schemas that Windows XP is designed to support. Windows 98 does not have to support IOAPICs, multiple root PCI buses, multiple-processor systems, and so on. When you are dealing with these hardware schemas, rebalancing becomes risky and therefore is not implemented in Windows XP except for very specific scenarios. However, PCI devices are required to be able to share IRQs. In general, the ability to share IRQs does not prevent any hardware from working.

The Plug and Play operating system settings in the computer BIOS do not generally affect how Windows XP handles the hardware. However, Microsoft recommends that you set the Plug and Play operating system setting to No or Disabled in the computer BIOS. For information about viewing or modifying the computer BIOS settings, consult the computer documentation or contact the computer manufacturer.

Manually assigning IRQs to PCI slots in the system BIOS as a troubleshooting method may work on some non-ACPI systems that use a standard PC hardware abstraction layer (HAL), but these settings are ignored by Plug and Play in Windows if ACPI support is enabled. If you need to manually assign IRQ addresses through the BIOS to a device on an ACPI motherboard, you must reinstall Windows to force the installation to use a Standard PC HAL. For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

mnosteele52 · Post by **mnosteele52** » Fri Apr 26, 2002 7:24 am

Good info Mike

, FYI I had an Irq sharing problem in XP on a pc I built and reset the CMOS (with the MB jumper) and it reassigned all of them fixing the problem.

Mike_W · Post by **Mike_W** » Fri Apr 26, 2002 11:26 am

I have reset CMOS too. All of my IRQ's are spread pretty well in XP, but, I have an obsession to get my NIC card IRQ on its own and was looking for some answers and found that article. I guess my NIC card or onboard Network Adapter is absolutely tied in with my USB Controller IRQ somehow. No matter what I do it is ALWAYS placed on the same IRQ together.

Lobo · Post by **Lobo** » Fri Apr 26, 2002 11:29 am

IRQ's most times use a few different IRQ's only, try changing IRQ of other thing sharing that IRQ

mnosteele52 · Post by **mnosteele52** » Fri Apr 26, 2002 11:29 am

I know it's a pisser, the only other thing to try (which I'm sure you already have) is move the card to another PCI slot. You can also disable your Com Ports (if you aren't using them) in your BIOS to free up the Irq's assigned to them. The problem I ran into was pretty much the same but it was a 56K modem sharing with 3 or 4 other things resetting the CMOS did fix it for me though.

Lobo · Post by **Lobo** » Fri Apr 26, 2002 11:40 am

Uninstall NIC adapter in devive manager first

Mike_W · Post by **Mike_W** » Fri Apr 26, 2002 12:11 pm

Done ALL of that! My NIC card is onboard, so I cannot change its slot. I tried disabling that NIC and installing a new one on a PCI slot, and thats when I got my dreaded second Realtek NIC that I've been bitching about. So, that didnt work.

Lobo · Post by **Lobo** » Fri Apr 26, 2002 12:44 pm

I guess Dude, get a Dell, lol, jk

Mike_W · Post by **Mike_W** » Fri Apr 26, 2002 12:50 pm

Lobo · Post by **Lobo** » Fri Apr 26, 2002 2:29 pm

Check in here Mike:

http://www.centralcomputer.com/Features ... s/CPUs.htm

Lobo · Post by **Lobo** » Fri Apr 26, 2002 2:52 pm

If it were me I would get sledge hammer and rest of tools and get rid of El cheapo onboard NIC

Lobo · Post by **Lobo** » Fri Apr 26, 2002 3:51 pm

I figured it out, get AOL, and mnosteele52 (Agent) will help you to be zoomer, lol

Mike_W · Post by **Mike_W** » Fri Apr 26, 2002 4:01 pm

Lobo · Post by **Lobo** » Fri Apr 26, 2002 4:10 pm

Try here:

http://www.google.com/search?hl=en&q=Ho ... Xp&spell=1

Lobo · Post by **Lobo** » Fri Apr 26, 2002 4:20 pm

Did you see #26 in help thread below in sig