[6.9.2] Unable to enable ASPM: it stays disabled even with policy and boot option (Ubuntu works, Unraid not)

Steps to reproduce:

1. correctly configure bios to support ASPM
2. Don't install any unnecessary components, no hard drives connected, no add-in cards installed
3. boot a fresh Ubuntu 21.04 from USB
4. check if ASPM is enabled

   lspci -vvvnnPPDq

   lspci_ubuntu.txt

5. boot Unraid 6.9.2
6. check if ASPM is enabled

   lspci -vvvnnPPDq

   lspci_unraid.txt

7. try to fix it with

   echo -n powersave > /sys/module/pcie_aspm/parameters/policy

    

8. try to fix it with boot option
   add pcie_aspm=force to /boot/syslinux/syslinux.cfg
9. reboot
10. check if ASPM is enabled
    lspci_unraid_aspm.txt
11. try to fix it with

    echo -n powersave > /sys/module/pcie_aspm/parameters/policy
    powertop --auto-tune

12. veryfy if boot option was used pcie_aspm=force
    unraid_aspm_syslog.txt

Expected Result:

ASPM should be enabled like it is in Ubuntu to save 4W of power in idle

Actual Result:

It is still disabled

lspci_unraid_aspm.txt

What setting or which driver could prevent ASPM or does disable ASPM? I don't know how to compare Ubuntu with Unraid to check what is different.

Workarround:

I know that Unraid and my hardware is capable of enable ASPM. Not only because Ubuntu does it, but because I can force it with manually setting it in the register https://wireless.wiki.kernel.org/en/users/documentation/aspm#enabling_aspm_with_setpci

After doing this hack for my root and ethernet interface, the power consumption gets reduced by 4W and powertop does tell that my CPU Package does now reach C7 instead of C2

Hardware Infos

server-diagnostics-20210727-1604.zip

About Me

I don't know if this error did exist in the previous versions because I'm currently evaluating Unraid and would like to know how important power saving issues are for you because I want to use it to make it more easy to reduce my servers power consumption. Power is expensive at my location, I can easily afford server upgrades based on power savings.
I would like to give the money to you for a license instead to my power provider