INFO: PCMCIA Interrupt Sharing Under Windows 98 (222821)


The information in this article applies to:

  • Microsoft Windows 98 Driver Development Kit (DDK)
This article was previously published under Q222821

SUMMARY

PCMCIA devices can utilize either shared (PCI) interrupts or non-shared (ISA) interrupts. Windows 98 determines the requested interrupt type by examining the TPCE_IR Interrupt Request Description Structure in the Configuration Table Entry Tuple. If the Share bit (bit 7) is set, Pccard.vxd attempts to route the card's IREQ# line to a PCI interrupt. If the Share bit is not set, PCCARD routes IREQ# to an ISA interrupt. If PCCARD determines that there are no interrupt lines of the proper type available, it will fail the CONFIG_FILTER message, causing the device to display error code 7 (CM_PROB_FAILED_FILTER) in Device Manager.

MORE INFORMATION

Under Windows 98 PCCARD enables PCMCIA IRQ sharing by default only for Modem class devices. PCCARD also enables IRQ sharing if it finds a registry value named EnableIRQSharing in the device's software registry branch with a nonzero value. For example, in an inf AddReg section you could use the following line to force PCCARD to allow IRQ sharing: 
HKR,,EnableIRQSharing,1,01,00,00,00
Modification Type:MajorLast Reviewed:5/6/1999
Keywords:kbinfo KB222821
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