Re: [PATCH] PCI/ASPM: Add back L1 PM Substate save and restore

["David E. Box" <david.e.box@linux.intel.com>]

Hi Thomas,

On Fri, 2023-06-30 at 18:58 +0200, Thomas Witt wrote:
> > On 30/06/2023 12:41, Mika Westerberg wrote:
> > > > @Thomas, below is an updated patch. I wonder if you could try it out?
> > > > This one restores L1 substates first and then L0s/L1 as the spec
> > > > suggests. If this does not work, them I'm not sure what to do because
> > > > now we should be doing exactly what the spec is saying (unless I
> > > > misinterpret something):
> > > > 
> > > >    - Write L1 enables on the upstream component first then downstream
> > > >      (this is taken care by the parent child order of the Linux PM).
> > > >    - Program L1 SS before L1 enables
> > > >    - Program L1 SS enables after rest of the fields in the capability
> > 
> > Sadly, same as before. With s2idle, power consumption stays up, but 
> > suspend/resume works, with deep it does not correctly suspend the PCI 
> > devices.

Mika is now out on extended vacation. We still need a solution that will enable
the L1 substate save/restore without breaking your system. I'd like to try to
get the power consumption lowered on your system while suspended with s2idle.
The s0ix self test script will really help to tell us where to start. You can
provide the results in the bugzilla.

The other thing we can do is find out why it only breaks under S3. It could be
timing related, so I've attached another patch to the bugzilla to test this.

https://bugzilla.kernel.org/attachment.cgi?id=304553

Please let me know if it works. Thanks.

David