Embedded System Considerations for Designing PCI Express Hot Plug Solutions

PCI Express Hot Plug is a feature that can help embedded devices improve serviceability, flexibility, and the user experience. Using this feature, a PCI Express endpoint may be replaced in a running system without having to turn the system off. A classic PCI Express implementation requires an extensive list of components including hardware, BIOS, OS, and drivers. Embedded systems often are bounded by constraints such as cost and form factors. It is often challenging to accommodate all the common components such as an attention button, manually operated retention latch, and various status indicators. This article discusses several design considerations to address these constraints while at the same time providing practical and reliable solutions for PCI Express Hot Plug in embedded systems. The successful handling of PCI Express Hot Plug is a system-level topic that involves proper configurations of BIOS settings, interrupts, as well as work partitioning among BIOS, OS, and driver. Incorrect implementation of PCI Express Hot Plug may compromise the safety and reliability of the products and may also induce all kinds of error conditions.

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