Welcome to our peer-to-peer forums, where owners help owners. Need help now? Visit eSupport here.

English Community

ThinkPad NotebooksThinkPad: P and W Series Mobile Workstations
All Forum Topics
Options

158 Posts

07-14-2017

Greece

846 Signins

5122 Page Views

  • Posts: 158
  • Registered: ‎07-14-2017
  • Location: Greece
  • Views: 5122
  • Message 21 of 26

Re:Vantage crashes

2021-03-14, 15:06 PM

Oddly enough, after resetting BIOS at default values (as you described), things stayed the same.

I am at a loss here...I was sure that following reset, things will return to normal.

Because Kernel DMA stayed ON (it seems it is the new default).

 

When I changed manually "Kernel DMA" OFF, things are back to normal (please see second attachment).

 

P52, 8850H, P2000, 2x16GB RAM
2x512GB NVMe, 1TB SSD
W10 pro
Reply
Options

158 Posts

07-14-2017

Greece

846 Signins

5122 Page Views

  • Posts: 158
  • Registered: ‎07-14-2017
  • Location: Greece
  • Views: 5122
  • Message 22 of 26

Re:Vantage crashes

2021-03-14, 15:24 PM
So, it looks like "Kernel DMA" ON disrupts things for Thunderbolt. Any ideas here ?
P52, 8850H, P2000, 2x16GB RAM
2x512GB NVMe, 1TB SSD
W10 pro
Reply
Options

6856 Posts

10-29-2009

United States of America

17788 Signins

165248 Page Views

  • Posts: 6856
  • Registered: ‎10-29-2009
  • Location: United States of America
  • Views: 165248
  • Message 23 of 26

Re:Vantage crashes

2021-03-15, 16:24 PM

Reset defaults does not change some security settings, such as Kernel DMA security.

Kernel DMA security does affect Thunderbolt security, but should not cause this problem.  That's why I'm thinking it might be Kernel DMA security in combination with some OS settings unique on your PC, but I don't have any idea currently what it could be.

Reply
Options

158 Posts

07-14-2017

Greece

846 Signins

5122 Page Views

  • Posts: 158
  • Registered: ‎07-14-2017
  • Location: Greece
  • Views: 5122
  • Message 24 of 26

Re:Vantage crashes

2021-03-15, 17:23 PM

Understand your point.

But still I do not have a unique machine. It's w10pro, 19042.867. 

Memory Integrity ON

Kernel DMA ON (BIOS)

TPM ON

Secure Boot ON

"Your device meets the requirements for enhanced hardware security"

No 3rd party antivirus or firewall. 

 

 

Dont know what other setting could be potentially relevant, but can provide on your suggestion.

 

P52, 8850H, P2000, 2x16GB RAM
2x512GB NVMe, 1TB SSD
W10 pro
Reply
Answer
Options

158 Posts

07-14-2017

Greece

846 Signins

5122 Page Views

  • Posts: 158
  • Registered: ‎07-14-2017
  • Location: Greece
  • Views: 5122
  • Message 25 of 26

Re:Vantage crashes

2021-03-19, 9:24 AM

Identified the problem in a forgotten policy setting.

  • Group Policy: Administrative Templates\System\Kernel DMA Protection\Enumeration policy for external devices incompatible with Kernel DMA Protection

That was set at:

0 - Block all (Most restrictive): Devices with DMA remapping compatible drivers will be allowed to enumerate at any time. Devices with DMA remapping incompatible drivers will never be allowed to start and perform DMA at any time.

 

It seems that the driver for Thunderbolt Controller - 15EB is not DMA-remapping capable.

Cannot understand the logic behind it, but it is what it is.

 

Changing the setting to anything else or the policy to "Non configured", returns things back to normal.

 

P52, 8850H, P2000, 2x16GB RAM
2x512GB NVMe, 1TB SSD
W10 pro

0 person found this solution to be helpful.

This helped me too

Reply
Options

1659 Posts

01-08-2021

Philippines

110 Signins

8365 Page Views

  • Posts: 1659
  • Registered: ‎01-08-2021
  • Location: Philippines
  • Views: 8365
  • Message 26 of 26

Re:Vantage crashes

2021-04-07, 17:40 PM

Glad to hear it's ok now.
Thank you for sharing it here

 

Best regards, 
Lorenzo_Lenovo



Did someone help you today? Press the star on the left to thank them with a Kudo!
If you find a post helpful and it answers your question, please mark it as an "Accepted Solution"! This will help the rest of the Community with similar issues identify the verified solution and benefit from it.

Follow us @LenovoSupport on Facebook and Twitter!

Reply
Forum Home

Community Guidelines

Please review our Guidelines before posting.

Learn More

Check out current deals!

Go Shop
X

Save

X

Delete

X

No, I don’t want to share ideas Yes, I agree to these terms