Detected Hardware Unit Hang

Detected Hardware Unit Hang. This article aims to help users troubleshoot Detected Hardware Unit Hang errors that usually lead to a heavy performance impact on client PCs.

This error is most commonly encountered when the server’s NIC is not fully compatible with Linux.

Example of the error manifestation

Resolution

You need to add the following to the kernel startup parameters:

pcie_asmp=off

In Debian this can be done by modifying the following file:

/boot/grub/grub.cfg

Add the following line to the GRUB_CMDLINE_LINUX_DEFAULT value:

pcie_asmp=off

It would look like this:

GRUB_CMDLINE_LINUX_DEFAULT="pcie_aspm=off"

(or have more parameters if there are some parameters in place already)

Updated on: 23/03/2026