FIX: Un-allowed DMA capable bus/device(s) detected - Windows 11

Credit goes to this posting:
https://superuser.com/questions/1345848/un-allowed-dma-capable-bus-devices-detected
I've edited it to make the process easier. It helped me solve the issue. Of course, use at your own risk and wear a helmet if you're going to tinker in the registry.
White-list the device​
Open Regedit
Navigate to Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\DmaSecurity\AllowedBuses
Grant yourself access to modify the registry key
Right-click AllowedBuses and go to Permissions
Make yourself the owner
Press Advanced
Next to Owner, make note of what it says (mine said SYSTEM)
Next to Owner, press Change
Enter your username (eg your Microsoft account email address)
Press OK
Grant yourself access
Press Add
Enter your username (eg your Microsoft account email address)
Press OK
Select your user
Tick Full Control
Press OK
Under AllowedBuses, create a new String Value
Run the following PS script which generates a .reg file (with all found PCI devices) in tmp directory and then imports it silently
Code:
$tmpfile = "$($env:TEMP)\AllowBuses.reg"
'Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\DmaSecurity\AllowedBuses]'`
| Out-File $tmpfile
(Get-PnPDevice -InstanceId PCI* `
| Format-Table -Property FriendlyName,InstanceId -HideTableHeaders -AutoSize `
| Out-String -Width 300).trim() `
-split "`r`n" `
-replace '&SUBSYS.*', '' `
-replace '\s+PCI\\', '"="PCI\\' `
| Foreach-Object{ "{0}{1}{2}" -f '"',$_,'"' } `
| Out-File $tmpfile -Append
regedit /s $tmpfile
Start removing added entries via regedit one by one while refreshing system info page and checking which entry makes it incompatible again
*Fun fact: Running the script again re-populates the list without duplicating/missing entries
You should find at least one entry that re-enables the System Information message. I had 2. (See photo below).
Keep ONLY the one(s) that trigger the incompatibility message
Make sure to remove the user account that took ownership of the registry folder. I did this by right clicking Allowed Busses-> advanced and deleting my account. No need to do anything else except confirm the original owner (System in my case) has been restored. Be warned that this may NOT be the correct way to restore ownership.
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This, unfortunately, does not work for me. After running the PowerShell script, I get entries added to AllowedBuses, but I still get the "Un-allowed DMA capable bus/device(s) detected" error.
The problem seems to be that I have multiple instances of some unallowed devices. When I run the Get-PnPDevice manually, I see everything, but you can only add a single instance of any given friendly name to the AllowedBuses key in the registry. For example, I have 12 PCI-to-PCI Bridge entries that have 5 different device ID's between them.
I haven't figured out how to whitelist everything I need to whitelist yet, and it seems impossible since I have multiple device ID's with the same friendly name that need to be added.

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shrike1978 said:
This, unfortunately, does not work for me. After running the PowerShell script, I get entries added to AllowedBuses, but I still get the "Un-allowed DMA capable bus/device(s) detected" error.
The problem seems to be that I have multiple instances of some unallowed devices. When I run the Get-PnPDevice manually, I see everything, but you can only add a single instance of any given friendly name to the AllowedBuses key in the registry. For example, I have 12 PCI-to-PCI Bridge entries that have 5 different device ID's between them.
I haven't figured out how to whitelist everything I need to whitelist yet, and it seems impossible since I have multiple device ID's with the same friendly name that need to be added.
Click to expand...
Click to collapse
Multiple instances of the same device can be fixed by appending 2, 3, 4 etcetera to the friendly names to make them unique.
I have five "PCI Express Root Port" devices with the same name but different device-id's, and this trick fixed the "Un-allowed DMA capable bus/device(s) detected" error for me.