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PC Hardware in a Nutshell, 3rd Edition
book

PC Hardware in a Nutshell, 3rd Edition

by Robert Bruce Thompson, Barbara Fritchman Thompson
July 2003
Beginner to intermediate content levelBeginner to intermediate
874 pages
38h 13m
English
O'Reilly Media, Inc.
Content preview from PC Hardware in a Nutshell, 3rd Edition

Verifying USB Interrupt Sharing Under Windows 2000/XP

To verify USB interrupt sharing status under Windows 2000 or Windows XP, from the Device Manager, choose View Resources by Type, and expand the Interrupt request (IRQ) item, as shown in Figure 24-12.

Windows XP Device Manager showing that this system dedicates PCI interrupts 19 and 23 to the two USB HCIs

Figure 24-12. Windows XP Device Manager showing that this system dedicates PCI interrupts 19 and 23 to the two USB HCIs

On recent motherboards, Windows 2000 and Windows XP typically assign a dedicated PCI interrupt above 15 to each device. On older motherboards, Windows 2000 and Windows XP typically assign a shared PCI interrupt to the HCI, as shown in Figure 24-13. Despite all assurances by hardware manufacturers and Microsoft that USB operates properly with a shared interrupt, that is frequently not true. If Windows has assigned a shared interrupt to USB, use the Device Manager to locate an unused interrupt, clear the Use Automatic Settings checkbox, and assign the unused interrupt to the HCI.

Windows 2000 Device Manager showing that this system shares one interrupt among the USB HCI and four other devices

Figure 24-13. Windows 2000 Device Manager showing that this system shares one interrupt among the USB HCI and four other devices

On the system shown in Figure 24-13, Windows 2000 has assigned one shared PCI interrupt among the USB HCI, the SCSI host adapter, the video card, the network adapter, and the sound adapter. Surprisingly enough, all ...

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Publisher Resources

ISBN: 059600513XErrata Page