It sees a similar patch in noble git source.

commit e88c171a892e485531eb1dbdcd45dbb046e1310b
Author: Maciej W. Rozycki <ma...@orcam.me.uk>
Date:   Fri Aug 9 14:24:51 2024 +0100

    PCI: Revert to the original speed after PCIe failed link retraining
    
    BugLink: https://bugs.launchpad.net/bugs/2089340
    
    commit f68dea13405c94381d08f42dbf0416261622bdad upstream.
    
    When `pcie_failed_link_retrain' has failed to retrain the link by hand
    it leaves the link speed restricted to 2.5GT/s, which will then affect
    any device that has been plugged in later on, which may not suffer from
    the problem that caused the speed restriction to have been attempted.
    Consequently such a downstream device will suffer from an unnecessary
    communication throughput limitation and therefore performance loss.
    
    Remove the speed restriction then and revert the Link Control 2 register
    to its original state if link retraining with the speed restriction in
    place has failed.  Retrain the link again afterwards so as to remove any
    residual state, waiting on LT rather than DLLLA to avoid an excessive
    delay and ignoring the result as this training is supposed to fail
    anyway.
    
    Fixes: a89c82249c37 ("PCI: Work around PCIe link training failures")
    Link: 
https://lore.kernel.org/linux-pci/alpine.deb.2.21.2408251412590.30...@angie.orcam.me.uk
    Reported-by: Matthew W Carlis <ma...@purestorage.com>


** Description changed:

  During NVME hot plug testing, some slot (in random) would be in
  downgrade speed on Ubuntu 24.04 even on latest v6.8.0-60. Same test for
  22.04 works well.
  
- Similar issue found on RHEL9.4 too where analyze and fix patch are below:
-  commit of a89c82249c37 introduce this bug;  
-  Whitley platfrom fix: dffe4cca2e36
-  Eagle Stream/Birch fix: d857ff7acaf2
+ Similar issue was found on RHEL9.4 too and analyze and fix patch are below:
+  commit of a89c82249c37 introduce this bug;
+  Whitley platfrom fix: dffe4cca2e36
+  Eagle Stream/Birch fix: d857ff7acaf2

-- 
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux-hwe-6.5 in Ubuntu.
https://bugs.launchpad.net/bugs/2112634

Title:
  nvme downgrade due to PCIe link training failure

Status in linux-hwe-6.5 package in Ubuntu:
  New

Bug description:
  During NVME hot plug testing, some slot (in random) would be in
  downgrade speed on Ubuntu 24.04 even on latest v6.8.0-60. Same test
  for 22.04 works well.

  Similar issue was found on RHEL9.4 too and analyze and fix patch are below:
   commit of a89c82249c37 introduce this bug;
   Whitley platfrom fix: dffe4cca2e36
   Eagle Stream/Birch fix: d857ff7acaf2

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux-hwe-6.5/+bug/2112634/+subscriptions


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