Re: [PATCH v1 0/2] PCI/ASPM: Fix LTR issues

From: Bjorn Helgaas
Date: Thu Feb 21 2019 - 23:58:29 EST


On Mon, Feb 11, 2019 at 04:55:33PM -0600, Bjorn Helgaas wrote:
> These are to fix a couple LTR-related issues found while investigating
> https://bugzilla.kernel.org/show_bug.cgi?id=201469
>
> I don't claim that these fix the whole problem of that bugzilla, but I
> think it's pretty clear that these are problems we need to fix, so I want
> to give these a little more exposure.
>
> Feedback welcome!
>
> ---
>
> Bjorn Helgaas (2):
> PCI/ASPM: Use LTR if already enabled by platform
> PCI/ASPM: Save LTR Capability for suspend/resume
>
>
> drivers/pci/pci.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++--
> drivers/pci/probe.c | 36 ++++++++++++++++++++++-------------
> 2 files changed, 74 insertions(+), 15 deletions(-)

I applied these to pci/aspm for v5.1.

I think Vidya is absolutely right that we also need to save/restore
the ASPM L1 Substates capability. But I haven't had a chance to
write that up yet, and I think these two patches by themselves
are an improvement even without ASPM L1 SS.

Bjorn