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

[Mika Westerberg <mika.westerberg@linux.intel.com>]

Hi Thomas,

On Wed, Jun 28, 2023 at 12:24:06PM +0200, Thomas Witt wrote:
> On 28/06/2023 08:46, Mika Westerberg wrote:
> > @Thomas, is there any particular reason you have this option in the
> > command line? There is possibility that S3 is not even fully validated
> > if the system advertises S0 low power sleep instead.
> 
> In fact, there is: Entering suspend-to-ram without setting
> /sys/power/mem_sleep to "deep", my laptop consumes about the same power as
> it would idling online. The manufacturer suggests setting that commandline
> parameter:
> 
> <https://www.tuxedocomputers.com/en/Infos/Help-Support/Instructions/Fine-tuning-of-power-management-with-suspend-standby.tuxedo#>

Thanks for the clarification.

> I just retested your patch with setting mem_sleep to "s2idle", and it no
> longer triggers the loss of PCI devices. I guess that could be the indicator
> that Björn asked for.

I wonder if the patch actually helps here now because the reason we want
to add it back is that it allows the CPU to enter lower power states and
thus reducing the power consumption in S2idle too. Do you observe that
when you have the patch applied?

> I attached the output of dmidecode to the bugzilla entry mentioned above:
> <https://bugzilla.kernel.org/attachment.cgi?id=304494>

Thanks!