On Tue, Jun 27, 2023 at 01:04:47PM +0300, Mika Westerberg wrote:
> On Tue, Jun 27, 2023 at 11:53:33AM +0200, Thomas Witt wrote:
> > On 27/06/2023 08:24, Mika Westerberg wrote:
> > > Commit a7152be79b62 ("Revert "PCI/ASPM: Save L1 PM Substates Capability
> > > for suspend/resume"") reverted saving and restoring of ASPM L1 Substates
> > > due to a regression that caused resume from suspend to fail on certain
> > > systems. However, we never added this capability back and this is now
> > > causing systems fail to enter low power CPU states, drawing more power
> > > from the battery.
> >
> > Hello Mika,
> >
> > I am sorry, but your patch (applied on top of master) triggers the exact
> > same behaviour I described in
> > <https://bugzilla.kernel.org/show_bug.cgi?id=216877> (nvme and wifi become
> > unavailable during suspend/resume)
>
> Thanks for testing! Can you provide the output of dmidecode from that
> system? We can add it to the denylist as well to avoid the issue on your
> system.
To me this says we don't completely understand the mechanism of the
failure. If BIOS made L1SS work initially, Linux should be able to
make it work again after suspend/resume.
If we can identify an actual hardware or firmware defect, it makes
good sense to add a quirk or denylist. But I'll push back a little if
it's just "there's some problem we don't understand on this system, so
avoid it."
Bjorn
