Problems Enumerating CardBus Devices with No Free IRQs

• Microsoft Windows 95 OEM Service Release versions 2, 2.1

SYMPTOMS

When you are running Windows 95 on a computer with CardBus slots, you may experience the following symptoms:

• When multiple PC Cards are installed and the computer is started, Windows may not start and you may receive the following error message:

        While initializing ... device V86MMGR: Insufficient memory 
        to initialize Windows.
  

• If Windows is running with one PC Card inserted, the computer may become unresponsive for several minutes when you insert another PC Card. When the computer returns from this busy state, Device Manager Reports the new card as disabled because of a resource conflict (code 12).

CAUSE

These symptoms can occur if there are not enough available IRQ lines for all the installed devices.

RESOLUTION

To work around this issue, make more IRQ resources available by disabling a device (such as a COM port or LPT port). Such devices can typically be disabled in Device Manager.

STATUS

Microsoft has confirmed this to be a problem in Microsoft Windows 95 OEM Service Release 2 (OSR2). An update to address this problem is now available, but is not fully regression tested and should be applied only to computers experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft does not recommend implementing this update at this time. Contact the vendor of your OEM version of Windows to obtain this update, or contact Microsoft Technical Support for additional information about the availability of this update.

MORE INFORMATION

If there are not enough available IRQ lines, there is no configuration that allows all devices to be active without a resource conflict. A device must be removed or disabled to free an IRQ line and allow the remaining devices to be configured successfully.

The update causes Windows to more quickly recognize that it cannot resolve the resource conflict. The new device is disabled as before, but more quickly.

Note that these symptoms may appear more readily with certain specific PC Card devices that use more than one IRQ line or cannot share IRQ lines with other devices.