Re: [PATCH] PCI: Add pci=safemode option

From: okaya
Date: Sat Jun 02 2018 - 13:57:28 EST


On 2018-06-02 13:43, Pavel Machek wrote:
Hi!

> And you should explain what exactly in PCI is "optional". Who defines
> this and where is that list and what can go wrong if those options are
> not enabled?

Bjorn and I discussed the need for such a "safe" mode feature when you
want to bring up PCI for a platform. You want to turn off everything as
a starter and just stick to bare minimum.

I can add a few words describing them. The goal of this option is to keep
base PCI features with MSI only. Things like PME, AER, ASPM, Extended
Tags, LTR, Relaxed Ordering, SRIOV are all considered optional. safemode
is certainly not intended for production environments.

I can taint the kernel as a suggestion.

I don't think tainting is required. even modern platforms should work
in the safe mode.

Yeah, concern was getting used to the safe mode and never running the full stack to fix the actual issues like getting away with crappy hardware and firmware.

It becomes a support issue for the community.


Pavel