TechSpot

Need to change IRQ numbers

By Karmashock
Jul 12, 2006
  1. I have several devices all using IRQ 22 (I've got several open spaces in the prime 1-16 area) and it makes the system slow, unstable, and unable to play sound properly.

    Now, my motherboard is PCIPnP compatible (very new intel chipset Mobo) and Windows XP Professional (SP2 fully updated) should certainlly allow me to change IRQ numbers from within the OS.

    Changing the slot the cards are in does NOTHING. Any card that's moved just gets the exact same number.

    The two devices that are conflicting are my harddrive controller and my soundcard which is the cheapest card creative is selling right now... about 25 USD... creative 24 bit whatever the heck... Anyway, I can see the area in the device manager where I'm supposed to be able to change IRQ settings but they're ghosted out. I've actually never seen this field be anything but ghosted out on any machine.

    Why is this? I see on the MS website and all over the net people just saying "go to the device manager and change the IRQ"... And because the card gets assigned the SAME IRQ no matter what slot I put it in, it's clearly not beyond the power of the hardware/software to handle different IRQs for different slots in the Mobo.


    Is this setting locked? Is there an app I can get that will just do the deed? Can I modify my registry to unlock this?


    What's going on here?

    I have even tried different sound cards and I get the same problem every time. The Creative card doesn't make the computer AS slow as other cards but the problem is still very noticable.
     
  2. fastco

    fastco TS Booster Posts: 1,122

    I found this on a previous techspot post, hope it helps:

    With the ACPI Hardware abstraction layer, you CAN'T really change IRQs in the operating system. And its likely if you change settings in the BIOS, it will just ignore those as well. Moving the card MAY help to change the IRQ, I don't know but again it might well not. ACPI pretty much gives the OS license to do what it wants with IRQs, and you will probably find loads of PCI devices lumped onto one IRQ and governed by ACPI. This is by design so that IRQ conflicts become a thing of the past. But as you have discovered, sometimes it becomes necessary.

    Here is how you could overcome this.
    -----------------------------------------------

    You Do This At Your Own Risk.
    --------------------------------------


    1)Right Click My Computer, Select Manage.
    2)Opens Management Console.
    3)Select Device Manager.
    4)Click on the + next to Computer (Top Icon under computer name)
    5)Reveals "Advanced Configuration and Power Interface PC"
    6)Right click that, select properties.
    7)Go into "Driver" tab
    8)Click "Update Driver"
    9)NEXT
    10)Display a list of known drivers for the device
    11)NEXT
    12)Click "Show all hardware of this device class"
    13)Under (Standard Computers), select "Standard PC"
    14)NEXT, NEXT, etc...

    15)Reboot and pray.


    Hopefully all will be well when you reboot. A number of things will be different. One will be that some advanced power management things DO NOT WORK. Particularly, its likely that if you select "shutdown" from the start menu, it will just shut the OS down, and you will be left with the old message "its now safe to turn your computer off" instead of the actual power going off, i.e. you will loose the ability to power down using software and will have to press the power off button on your case. You may also get IRQ conflicts because you will have lost advanced IRQ management and will instead have to rely on the BIOS trying to do the best it can to make everything work. Try to set "Plug and Play OS installed" to NO in your BIOS if you have such a setting. You might also want to run a "Reset ESCD Data" as well first time round.

    Good luck. You might need it.
     
  3. Karmashock

    Karmashock TS Rookie Topic Starter Posts: 223

    Ok, why can't I change IRQ numbers if Microsoft says I can, i've seen fixes posted on the net that suggest that it be done, and I can clearly see the GUI for that feature? It makes no sense.

    Furthermore, if the OS has control of the IRQ numbers then I should be able to override it somehow... I mean... this is just crazy...


    As an additional note... This machine did not initially have an IRQ problem. It worked fine for about 6 months and then just started getting unstable and rebooting randomly. Then the registry hive got corrupted and I went to the backup install of the OS that I put on all my computers when all hell decides to break loose... That got me into the OS again but the computer STILL had the same problem on a practically virgin copy of XP. All it had installed on it was drivers... the very same drivers that had worked for 6 months on the other install until it started rebooting like crazy. Anyway, I figured out that the sound card was the problem because it had no problem in safemode and if the sound card was disabled the system ran perfectly. So I tried moving the card around and it just kept getting assigned to the same IRQ as the Harddrive controller of all things... meaning that my sound card is basicaly fighting for control of the same IRQ as the HD. I couldn't get the damn thing to change so I decided to buy a new sound card from a better company.

    I got a cheapo creative card and that helped a lot. However, it's still not right... the computer is basically incapable of doing more then ONE thing at a time. I can't so much as browse websites can copy something at the same time. Games work fine... movies work fine... so long as that's ALL I'm doing.


    It seems like the OS changed the way it handled IRQ's or system resources about a week ago basically at random. Is there anyway to get it to 'try again'? Because the machine is basically usuable as it is...

    This is not a weak machine... it's fairly well kitted out 1600 dollar rig... and it's running like a 800mhz POS most of the time now...
     
  4. fastco

    fastco TS Booster Posts: 1,122

    I don't know what else to tell you to try. I know in WIndows 98 I used to be able to manually assign IRQ's but I can't in XP, it won't let me. It is possible IF the bios lets you but many computer manufacturers don't want you messing with the IRQ settings and they disable it in the bios.
     
  5. Karmashock

    Karmashock TS Rookie Topic Starter Posts: 223

    the Bios lets me "reserve" IRQ numbers... obviously just for 1-16... apparently for ISA cards. Which is odd because the board has no ISA ports...
     
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