I have a x4 PCIe(Host) Lane which I am connecting to a PCIe Switch. With PCIe Switch , I have connected 8 PCIe SSD Drives(End points).

When I am doing power up, the PCIe Bus is getting enumerated & my drives are coming up. My design supports hot plugging of PCIe Drives. During power up , all 8 drives will be enumerated & will be allocated resources.I need clarification about below mentioned cases :-

  1. In case, I want to remove a drive & hot plug another drive, will it get auto-enumerated?
  2. In case, I have only put 6 Drives initially. After Powering up, I am hot plugging another 2 drives, will they get enumerated on the go?

In both the above cases, I don't want to enumerate entire PCIe Bus as another drives might be doing some operation. Only, the specific hot plugged drive should get enumerated. Please help.

  • \$\begingroup\$ I think this is going to be very software and driver dependent. \$\endgroup\$ Jun 30, 2015 at 14:59
  • \$\begingroup\$ Does all the hardware, including motherboard and BIOS support hot plugging. ExpressCard slots in laptops have the capability, but alas most motherboards with PCIe slots don't. If there isn't support, the BIOS enumerates the bus at power on, but not after hot-plug (see here). \$\endgroup\$ Nov 8, 2015 at 5:05

1 Answer 1


PCIe is designed to be able to support hot-plugging.
If all of your hardware and software implement this correctly, it will work.

You didn't name names, so only you can find this out.

  • \$\begingroup\$ HW Hot Plug is implemented perfectly. Looks like some driver dependency. The Drive is getting power during Hot Plug but link is not coming. It has something to do with resource allocation. \$\endgroup\$
    – Oshi
    Jul 1, 2015 at 7:14
  • \$\begingroup\$ Is the physical link being established? Most switches have LEDs to show the state of the link. Physical layer link partner establishment is completely hardware based. \$\endgroup\$ Oct 9, 2015 at 10:49

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