Re: [PATCH] PCI: Always lift 2.5GT/s restriction in PCIe failed link retraining

[Matthew W Carlis]

On Mon, 23 Feb 2026 23:14:37 +0000, Maciej W. Rozycki wrote:
>  I argue that by applying this change the issues with NVMe hot-plug will 
> be sorted while keeping the configuration working that 
> pcie_failed_link_retrain() is needed for.  Win-win.

I don't think that what you are saying is true there is invariably going to be
some other consequence of this change.. Its hard to believe there can be any
changes to the pci drivers that won't break something.

>  I note that active links are unaffected, so to say it's meddling with the 
> link on every device is I think a bit of an overstatement, and reports of 
> issues are from a few people only...

There is no discrimination about which device it can be invoked on..
I'm looking at a fleet of millions of hot-plug'able devices.... I don't really
know if it matters how many people report an issue, I think what probably
matters is making the right change. Initially was there any other reports
of the quirk helping with other devices besides the delock 41433?

>  What outcome would you envisage had I taken the approach from this update 
> right away with the original change?  My only fault was I have no use(*) 
> for PCIe hot-plug and did not predict the impact there. 

What I'm seeing now is an overall confusion about whether a link failed to train
to gen 1 or was recovered by the quirk or recovered on its own etc... In my systems
I would prefer to NEVER invoke the quirk under any circumstances because I expect
my devices to work. With the quirk it becomes more unclear about what the cause
of a link issue might have been or whether it was even a real link issue in the
first place or some weird timing.. 

-Matt