I'm running Centos 6.8 with 3.18.41-20.el6.x86_64 Xen kernel. Due to this problem (e1000e Detected Hardware Unit Hang) I updated my grub.conf appending arg pcie_aspm=off to the default kernel, but I can't reboot this hypervisor at the moment. I would like to set the variable at runtime if possible.

This is my current status:

# cat /sys/module/pcie_aspm/parameters/policy
[default] performance powersave

Is it possible to echo off > /sys/module/pcie_aspm/parameters/policy in order to achieve the same result? I think it doesn't make sense because off basically disables the function. What's the best option then? Would performance be a good workaround for my case? (see Centos6 ASPM guide)


you have to put changes in grub and rebuilt grub to take effect, after reboot it will show you to :-

cat /proc/cmdline BOOT_IMAGE=/vmlinuz-3.10.0-327.el7.x86_64 root=/dev/mapper/rhel-root ro crashkernel=auto rd.lvm.lv=rhel/root rd.lvm.lv=rhel/swap rhgb pcie_aspm=off quiet LANG=en_US.UTF-8

  • You could also edit boot parameters when booting. – Rolf Apr 17 '18 at 21:58

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