Microsoft KB Archive/279256

= How to disable IRQ sharing for 16-Bit PC cards that do not support ISA-to-PCI routed interrupts =

Article ID: 279256

Article Last Modified on 4/25/2007

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APPLIES TO


 * Microsoft Windows XP Home Edition
 * Microsoft Windows XP Professional
 * Windows Vista Business
 * Windows Vista Enterprise
 * Windows Vista Home Premium
 * Windows Vista Home Basic
 * Windows Vista Ultimate
 * Windows Vista Business 64-bit Edition
 * Windows Vista Enterprise 64-bit Edition
 * Windows Vista Home Premium 64-bit Edition
 * Windows Vista Home Basic 64-bit Edition
 * Windows Vista Ultimate 64-bit Edition

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This article was previously published under Q279256



Important This article contains information about how to modify the registry. Make sure that you back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows registry



SYMPTOMS
The R2 PC Card does not start, and you see the following error message in Device Manager:

This device is either not present, not working properly, or does not have all the drivers installed. (Code 10)

Try upgrading the device drivers for this device.



CAUSE
This behavior occurs because some R2 PC Cards do not support interrupt request (IRQ) resource sharing. In Windows XP or in Windows Vista, 16-bit PC Card (PCMCIA) PCI readers can use R2 PC Cards (the 16-bit ISA type) without requiring an ISA runner paddle to obtain ISA interrupts.



RESOLUTION
Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

To resolve this behavior, disable the ISA-to-PCI routing feature to allow these PC Cards to function in laptop computers:  Start Registry Editor (Regedit.exe). Locate and click to select the following key in the registry:

 On the Edit menu, click New, click DWORD Value, type DisableIsaToPciRouting in the NewValue box, and then press ENTER. Click to select DisableIsaToPciRouting, click Edit, and then click Modify. In the Value data box, type 1, and then click OK. Quit Registry Editor.</li></ol>

This procedure disables PCI routing for 16-bit PC Cards. With this feature, you can successfully install 16-bit PC Cards on computers that are low on ISA interrupts by using a shared-PCI interrupt.

Note: If you disable this feature, the device could potentially display an error code 12 (not enough free resources) in Device Manager if there is not a suitable free interrupt for the card to use. You may have to disable an unused device or port to make an IRQ available for the card.

Keywords: kbprb KB279256

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