It sees a similar patch in noble git source.
commit e88c171a892e485531eb1dbdcd45dbb046e1310b
Author: Maciej W. Rozycki <[email protected]>
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/[email protected]
Reported-by: Matthew W Carlis <[email protected]>
** 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
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https://bugs.launchpad.net/bugs/2112634
Title:
nvme downgrade due to PCIe link training failure
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