netdev - PCI: Work around PCIe link training failures

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Message-Id: <20240722193407.23255-1-mattc@purestorage.com>
Date: Mon, 22 Jul 2024 13:34:07 -0600
From: Matthew W Carlis <mattc@...estorage.com>
To: macro@...am.me.uk
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Subject: PCI: Work around PCIe link training failures

Sorry to resurrect this one, but I was wondering why the
PCI device ID in drivers/pci/quirks.c for the ASMedia ASM2824
isn't checked before forcing the link down to Gen1... We have
had to revert this patch during our kernel migration due to it
interacting poorly with at least one older Gen3 PLX PCIe switch
vendor/generation while using DPC. In another context we have
found similar issues during system bringup without DPC while
using a more legacy hot-plug model (BIOS defaults for us..).
In both contexts our devices are stuck at Gen1 after physical
hot-plug/insert, power-cycle.

Tried reading through the patch history/review but it was still
a little bit unclear to me. Can we add the device ID check as a
precondition to forcing link to Gen1?