Re: [PATCH v2] PCI: Avoid link retraining on empty ports when lifting speed restriction

> Since commit 72780f796468 ("PCI: Always lift 2.5GT/s restriction in PCIe
> failed link retraining") the Target Speed quirk lifts a firmware-imposed
> 2.5GT/s restriction on any downstream port, without checking whether the
> link is up.  Where nothing is plugged in, the retraining that follows can
> never complete, so each attempt costs PCIE_LINK_RETRAIN_TIMEOUT_MS.  The
> quirk makes two of them -- the initial one and the restore on the error
> path -- adding a fixed 2 s to every boot.
> 
> On an MSI PRO Z690-A WIFI DDR4 (Intel 600 Series PCH) with one empty x1
> slot, running v7.2-rc5:
> 
>  0.541 pci 0000:00:1c.0: removing 2.5GT/s downstream link speed restriction
>  1.541 pci 0000:00:1c.0: retraining failed
>  2.541 pci 0000:00:1c.2: [8086:7aba] type 01 class 0x060400
> 
> [ ... ]
>  LnkCtl2: Target Link Speed: 8GT/s
> 
> Fixes: 72780f796468 ("PCI: Always lift 2.5GT/s restriction in PCIe failed link retraining")
> Cc: [email protected]
> Signed-off-by: Andreas Wild <[email protected]>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=1